Short answer:

There's really no such thing as "the average person"; understanding history (and sociology) is substantially about understanding that. With that proviso, no regime likes criticism, and repressive regimes have the means and the inclination to regard dissent as impermissible, and a target of suppression. How they respond can vary from time to time, from person to person, from country to country, from tradition to tradition; reactions can range from "no reaction" to mild intimidation, to more extreme measures up to and including torture and murder. Just which it might be is all about all the ways in which no one, and no regime is ever really "average"

The prominence of the dissenter can matter-- but regimes whose only check is their own calculation of interest are quite capable of salutary brutality against "nobodies". There's nothing to be gained from a system of repression that carries with it immunity for some-- the entire purpose of such a system is to make everyone obedient, whether prominent or "ordinary".

NB -- I am discussing both "totalitarian" and merely "authoritarian" regimes here, because when it comes to suppression of dissent the distinction isn't particularly useful.

Russia today is moderately repressive, but not nearly so much so as in its past.

Discussion:

Totalitarian regimes aren't monotonically violent or tolerant. You could be killed for any reason, or no reason at all. The poet Osip Mandelstam was killed for writing a rude poem about Stalin. Hans and Sophie Scholl and some of the other White Rose movement were killed for advocating non violent resistance to the Nazis. Russia today isn't nearly so severe-- Putin's regime is likely the most tolerant to have ruled Russia for any appreciable number of years. Less repressive than the Soviets, less repressive than the Tsars. Still, you push too far, and they can be very unpleasant, indeed murderous -- or at least countenancing murder carried out by regime allies.

If you look at the intelligence reports that totalitarian leaders followed, they often care intensely what "ordinary people" might say (or tweet) about them, but they care more what more influential people say. Napoleon's secret police reported to him almost daily on domestic security, both international spying and ordinary popular mood. Attract enough of the wrong kind of attention, and something bad could happen to you. That something bad might be a visit to the police station for a "cup of tea" as the Chinese tend to do to deliver a warning. It might be a beating. It might be internal exile. It might be a denunciation by your neighbors and a trip to the Gulag.

There's no "average" to systems which are designed to terrorize a population, and which require their obedience. A criticism might be ignored, or it might be punished with severity; it is in the nature of totalitarian regimes that they're unconcerned with ideas like "proportionality". They're much more concerned with the use of force and intimidation to achieve political control. Joseph Fouché, Napoleon's Police Minister, on occasion ordered the release of prisoners with the notation "assez puni" = "punished enough". That's not a judicial decision, just a secret policeman's own intuition about the balance between intimidation and national productivity.

One interesting question is to examine totalitarian regimes in comparison to each other and to themselves at different times. Regimes may be brutal, but they are not identically brutal at all times and place. What would get you killed in the Soviet Union in 1937 was punished much less severely in 1960. What would get you killed in Hitler's Germany differed from what might get you killed in Mussolini's Italy or Franco's Spain.

In China today, the Internet has made it easy for us to map what the regime's sensitivities are. Interestingly they do not typically object to criticisms of local authorities for corruption or incompetence - but they respond much more aggressively to mention of certain forbidden topics: the Dalai Llama, the artist Ai Weiwei, the Falun Gong; and they are most aggressive about any suggestion of mass meetings or protests.

But today's repression in China is still light compared to the brutality of the past. The Yongle Emperor -- the much admired "second" Emperor of the Ming Dynasty ("second" is in quotes because he did away with the true second and expunged him), carried out a particular bloody massacre of not just a scholar who defied him, but the scholar's entire extended family-- this was referred to as "Nine Familial Exterminations"; the practice of punishing the extended family can be seen today in North Korea. Granted that Fang Xiaoru and the "Four Martyrs" were prominent scholars -- eg perhaps not so "ordinary" -- but the brutality meted out to them (at least as the story goes) for criticizing the regime was extraordinarily brutal.

Its notable that authoritarian regimes are often highly sensitive to dissent among emigré communities-- they don't just punish dissent in the country, they are often highly sensitive to dissent among their countrymen abroad, and may be differently sensitive to comments made abroad vs those made domestically.

Sources:

Savella, Italo G. “Arturo Bocchini and the Secret Political Police in Fascist Italy.” The Historian, vol. 60, no. 4, 1998, pp. 779–793.

Harris, James. "The Great Fear: Stalin's Terror of the 1930s" (Oxford University Press:2017)

BURROWS, SIMON. “Despotism without Bounds: The French Secret Police and the Silencing of Dissent in London, 1760–1790.” History, vol. 89, no. 4 (296), 2004, pp. 525–548.

Johnson, Richard J. “Zagranichnaia Agentura: The Tsarist Political Police in Europe.” Journal of Contemporary History, vol. 7, no. 1/2, 1972, pp. 221–242.

Thurston, Robert W. “Police and People in Moscow, 1906-1914.” The Russian Review, vol. 39, no. 3, 1980, pp. 320–338.

King, G., Pan, J., & Roberts, M. E. (2014). "Reverse-engineering censorship in China": Randomized experimentation and participant observation. Science, 345(6199), 1251722. https://doi.org/10.1126/science.1251722

Ditmanson, Peter. “Venerating the Martyrs of the 1402 Usurpation: History and Memory in the Mid and Late Ming Dynasty.” T'oung Pao, vol. 93, no. 1/3, 2007, pp. 110–158.

Kelly, G. A. “From Lèse-Majesté to Lèse-Nation: Treason in Eighteenth-Century France.” Journal of the History of Ideas, vol. 42, no. 2, 1981, pp. 269–286.

There are a lot of variables on what you criticize, who is the target (system vs a specific person), what is your position within the society, and what you trying to achieve with the criticism. In Czechoslovakia, the regime was totalitarian between 1948-1989, but there is a huge difference in living in the peak of the Red Terror in 1952 versus benevolent 1967 or Czechoslovakia under a direct Soviet control in 1977. Czechoslovakia was also not a single man dictatorship, but a collective dictatorship of the communist party where various factions wielded influence to achieve their power and goals and undermining others within the same party system. Therefore, criticism within the party would indicate that there was a power struggle lets be on the local or state level. Criticism from a person who was not a member of the communist party would be looked harshly.

In the 50s under Gottwald (+1953) and Zapotocky (+1957), criticism of the government would land you in prison under the laws of § 231/48 (Law of 231) . Widespread strike wave in 1953 by workers were suppressed and many were imprisoned. The government did not accept any criticism of its policy and anything that would make the communist regime look bad was not tolerated. This is nicely depicted in the book A. London, Confession and H. Kiraly, Under a Cruel Star. In the 60s, the authority of the communist party weakened, and the frustration of the population was directed against the highest leadership. While it would be inconceivable to criticize the president and the leadership of the party in 1960, it became common in 1967. This channeled to the streets, first among students, later to a broad population who demanded true democratization in 1968. The years between 1967-1969 witnessed widespread, nationwide anti-government, anti-communist, anti-soviet demonstrations, general strike, street violence, blockage of the Soviet garrisons, and sometimes toppling of the communist symbol. The communist party enforced the control of the situation by the summer of 1969 and for the next 20 years, suppressed any criticism. The party was also thoroughly purged not allowing free discussion panels that were common between 1957 and 1969.

Even in the last two years of the communist regime, the situation barely relaxed. I went to demonstrations both in 1988 and 1989, seen people getting beaten up, hosed down, chased by police, and getting arrested. In 1967 or 68, prior the Soviet invasion, the demonstrations would generally only involve police overseeing situation, but not beating. 20 years later, it necessitated the country to mobilize to overthrow the totalitarian regime.