The USSR implemented socialism successfully. The bumps it ran into along the way were bumps any socialist state would have to run into, especially the first set of socialist states. After all, it was socialism that ended famine, doubled life expectancies, went from squalid shacks for most people to functional apartments for all, and much more.

Re-criminalizing homosexuality was certainly a mistake, but was not especially repressive compared to peer countries. Moreover, this wasn't particularly straightforward. The soviet union was still enormously socially progressive contextually, even if existing in siege did end up hampering that progress.

The USSR was also the opposite of anti-semitic. Anti-semitism was punishable by death. Moreover, Nazis and their sympathizers warned of "Judeo-Bolshevism," as the soviet union fought heavily against the popular anti-semitism at the time. George Orwell in fact kept a list of Jews and communists, and was a professional snitch for the British government.

As for freedom of religion, it still existed in the USSR. The CPSU took an active stance against religion, as dialectical materialism leaves no room for religion, but one thing we did learn from the soviet experience is that you cannot force people out of religion. They have to develop out of it, though you can help that along. Still, the USSR had churches and existing religion, just preventing it from gaining a hold over society.

The USSR didn't fail, it was dissolved from the top-down. The economy didn't explode until after it dissolved. Nobody really believed it would dissolve until right before it did. It's dissolution was not inevitable.

No worries on the sources, being a communist in the English-speaking world pretty much requires doing a good deal of research due to the sheer number of anti-communists.