Hi, fellow fiction writer here! I've done some research for my own writing, so I think I can answer some of your questions (particularly regarding the USSR itself, not the rest of the Eastern bloc). I wound up writing quite a bit, so I hope I haven't completely made your eyes glaze over. If you have any further questions, or you'd just like to chat/brainstorm with another writer, feel free to DM me.

Regarding the question of what jobs or lifestyles - there are a lot of options, and it depends a great deal on when in the Soviet Union we're talking about, and how old your character would be. The period of worst repressions was 1936-1937 - but people who were adults during that period are likely old enough to remember life under the Tsars. They would have been in nonstop contact with unapproved content before the Revolution. Even if your character wasn't born before the Revolution, their parents or grandparents might well have been. Many parents or grandparents passed on religious teachings to their children in secret.

Even after the Revolution, there was a period of comparative liberality before Stalin took power - the Bolsheviks legalized abortion, decriminalized homosexuality, loosened gender roles and de-emphasized marriage. Then when Stalin came along, the sodomy laws came back, abortion was banned, and there was a great deal more emphasis on traditional, monogamous marriage with a traditionally feminine wife who stayed home and didn't work. So that is to say, if your character was an adult during the 20s, they might have been exposed to explicitly Bolshevik ideals which would have then become 'heretical' in the 30s.

A lot of the ideas that were 'heretical' in the 30s also became openly proclaimed in the 40s - Stalin lifted a lot of the restrictions on religion during WWII. The regime platformed explicitly religious anti-Nazi propaganda, intended for Christian, Muslim, Jewish and Buddhist audiences, at home as well as abroad. Religion was widespread among Soviet soldiers during WWII, and as far as I understand it from what I've read, it was largely unrestricted by the regime. Jeff Eden's book 'God Save the USSR,' about Islam in the USSR during the war years, has an anecdote about a man in the NKVD (secret police) who, according to his testimony, spent most of WWII preaching about Islam and leading his fellow soldiers in prayers. He also relates a conversation he had with a Christian Red Army officer about how they essentially worshiped the same God. Fascinating book.

In turn, a lot of the ideas that were 'heretical' in the 40s became openly proclaimed in the late 50s after Stalin died and Krushchev denounced him. For three decades, Stalin had been the object of worship by the regime; now, in 1956, the official line became that Stalin was a homicidal tyrant.

I don't think there was ever a 100% clear line between "approved" and "unapproved" ideas. This was one of the things that made living under Stalin so terrifying; you didn't know if something that was okay yesterday would still be okay today. But it means that whatever ideas you want your character to have come into contact with - she could have come into contact with those ideas /from/ the regime itself, or at least from approved sources. The regime was also pretty hypocritical - if the Party is talking a big game about anti-imperialism and equality and railing against segregation in America, and your character is a sincere communist who agrees with all of that - she might think "hey, this looks a lot like that capitalist imperialism we're supposed to be against!" when her friend gets denied for a high-ranking position on the basis of being Jewish. (Jews were not allowed in the upper ranks of the Soviet government from the 1950s until the fall of the USSR; if you weren't Jewish but one of your parents was, you'd be allowed in the government but not in the KGB.)

In the late period, the 80s and 90s, things loosened up a lot and I believe it was much easier for ideas from outside the USSR to come inside. I haven't done as much research on this period, but if this is something you'd like to know more about, you'll find it to be pretty easy, because the 80s and 90s are still in living memory.

These are all ways that your character could come into contact with unapproved ideas /without/ having any particular job - but you did ask about jobs, so let me address that in my next comment.

Soviet whaling was one of the few industries where a laborer could be granted access to the Western world and the materials that would only be available outside of the USSR. Soviet whaling vessels occasionally made port calls, largely in South America, Asia, and Oceania, and allowed supervised shore leave for their sailors. Groups of three to five would be granted time in port - almost always under the eye of an officer or established Party member to dissuade defection - and be given the opportunity to experience and purchase goods to bring home. Often times, these goods would be flipped to the Russian black market or kept as status symbols by the whalers and their families.

The Soviet Union allowed this limited access as an opportunity at soft propaganda to the outside world, whereby whaling vessels and their sailors could be carefully constructed as a triumph of the Soviet socialist systems. Ryan Tucker Jones notes an irony in Soviet domestic economy where, in a system where the state largely provides the expenses of living while being limited in supplying consumer goods to purchase, whaling crews were often sitting on decent reserves of cash (whaling being a field of relatively high wages to other Soviet jobs) unable to be spent at home. With the occasional supplement of hard cash in foreign ports, Soviet whalers were "let loose" in a sense to spend their wages overseas, giving a wealthy image of the Soviet sailor. With the addition of women onboard whaling vessels, a practice that was alien to Western crews, and the continued earnest promotion of collective labor imagery and hard work, the Soviet Union was able to use their whalers as the ideal outcome of their socialism: a progressively better world of hard work, high wage, and gender/social equality.

For their part, the whalers and crews largely bought into the socialist model. Shipboard newspapers were quick to extoll the virtues of their work, praise the meeting or exceeding of production quotas, and quick to identify individuals who were personifications of the ideal Soviet (and quick to identify those who came up short in their conduct, drunkenness was a recurrent problem for sailors on whaling voyages, at sea and in ports). Soviet whalers were receiving high wage for the strenuous time spent at sea hunting and processing whales and could often expect bonus pay in their travels to polar territory and by rising above state quotas for catches. In many ways, the whaling ship crew saw how their hard work and long months in Antarctic seas brought the fruits that collective labor wrought. In that sense, the Soviet socialism could be said to have been working well in the whaling world, even if it was destroying whale stocks globally.

Sources:

Red Leviathan: The Secret History of Soviet Whaling by Ryan Tucker Jones

Too Much Is Never Enough: The Cautionary Tale of Soviet Illegal Whaling by Ivashchenko & Clapham

Soviet Illegal Whaling: The Devil and the Details by Ivashchenko, Clapham, & Brownell

I see you included Slovenia and Croatia in your post. Slovenia & Croatia were a part of Yugoslavia, which was very different - a lot more liberal. Yugoslavia strongly distanced itself from the Soviet bloc and actually had friendlier & more cordial political & economic relations with Western countries than with the Soviets. Seeing what the Soviets did in Hungary and Czechoslovakia, Yugoslav leadership was highly distrustful of the USSR.

Yugoslav people were able to travel to other countries freely, and a lot of them had relatives working in Germany, Austria, Switzerland etc. There was some state propaganda about how great socialism/communism was, but the level of indoctrination was much lower than in the USSR and the Warsaw pact countries. As people were free to travel abroad, they could see for themselves that life was nicer in the West. We watched Austrian TV and travelled to Austria, Germany & Italy often (to visit relatives and for shopping). Also, the Adriatic coast was a popular tourist destination for people from Germany, Austria, the Netherlands etc.

I was a little kid in the 1970s, and a teenager in the 1980s - life was quite easy & carefree for a lot of people, which is why a lot of older people still have fond memories of that time. Having said that, it was not a democracy, economy relied on foreign debt from the West and the system was unsustainable & bound to fail.

The questions that you're raising are very complex, and rather than giving you advice about who would know what where, I'm going to recommend a paper: "The Tenacious Liberal Subject in Soviet Studies" by Anna Krylova. You can read it yourself (the link is a PDF) although I'll admit it's not terribly accessible.

Krylova describes how during the early Cold War period, Western writers became attached to a particular understanding of people living under communism (or "totalitarianism", as people referred to it at the time) as having a subjective experience and sense of identity that was totally different from their own, and in fact the opposite of it. People in the liberal democratic world acted as free individuals able to make independent decisions based on their own judgement, but people living in Communist regimes were forced to internalize official ideology and logic. Either they were totally convinced true believers, or they were sort of psychologically shattered and unable to think in a way that wasn't structured by the regime. Later, Western writers began searching for signs that the "liberal subject" hadn't been extinguished in the Soviet Union, and that some Soviet people really did think like them. Some people were brave dissidents who spoke up for the truth, others were opportunists who toed the party line in public but laughed about its absurdity in private, or else they were people continually struggling to reconcile official ideology them with their individual experiences and perspectives. The point isn't that these different portraits don't describe anybody in the Soviet Union or other Communist countries (for sure there were definitely cynical opportunists and true believers there as everywhere else in the world), but rather that these particular psychological frameworks tell us as much about Western historians, their preoccupations, and their societies as it does about the experience of people in Communist regimes.

The paper is making an argument about how Western historians have written about the Soviet Union, but I think it's also relevant to the question you're asking. I would also advise you to look very closely into the particular country and time period that you're setting your story, since the answers to the questions you posed will be very different in the Soviet Union in 1932, Czechoslovakia in 1952, or Hungary in 1972, and also different depending on the particular social environment you're looking at.