To answer your headline question in a word, awful. It did improve post-Stonewall and into the 1990s. To answer your subsequent questions; pretty much nothing. It wasn’t as bad as in the days when the penalty for homosexuality was death, and I am mostly focusing on the post-WW2 era here, but consider this;

At the end of the 1960s, homosexual sex was illegal in every state but Illinois. Not one law — federal, state, or local — protected gay men or women from being fired or denied housing. There were no openly gay politicians. No television show had any identifiably gay characters. When Hollywood made a film with a major homosexual character, the character was either killed or killed himself. There were no openly gay policemen, public school teachers, doctors, or lawyers. And no political party had a gay caucus.

This is from Stonewall: The Riots That Sparked the Gay Revolution - the definitive account of the event - by David Carter. In the opening stages of the book he lays out the preexisting situation for gay people in the USA, and I am primarily drawing from it (and a couple of the works it quotes) here.

There had been a hardening of the laws post-WW2, spurred on by McCarthyism and anti-communist fervour:

By 1961 the laws in America were harsher on homosexuals than those in Cuba, Russia, or East Germany, countries that the United States criticized for their despotic ways... In 1971 twenty states had “sex psychopath” laws that permitted the detaining of homosexuals for that reason alone. In Pennsylvania and California sex offenders could be locked in a mental institution for life, and in seven states they could be castrated.

In April 1953 Eisenhower signed Executive Order 10450, which made “sexual perversion” grounds for government dismissal, and the US government shared those records with private sector employers. Once you were fired from the government job, you were basically prevented from employment in the private sector too.

Transgender people were completely smothered - the treatment was just as harsh, but administered differently. Where a gay man could face being electroshocked, lobotomised, and castrated, a trans person was simply stopped from even getting that far - stopped by exploring their identity by, for example, being arrested for wearing clothes “inappropriate” to their sex. It’s not that they faced horrific penalties for being what they are - they were prevented even reaching that stage.

To sum up:

Thrice condemned — as criminals, as mentally ill, and as sinners — homosexuals faced a social reality in post–World War II America that was bleak, if not grim.

Again, the primary source I’ve used is Stonewall: The Riots That Sparked the Gay Revolution by David Carter, with reference to some of the sources he’s employed.