I think what people don’t fully understand is that Marxism is meant to be scientific. That means that there will likely be many imperfect and failed attempts at building a socialist society before one comes along that is stable enough to outlast outside interference from capitalist states.
As such, most people I know who like the USSR are also it’s biggest critiques. Unfortunately, there is so much misinformation about the USSR that most discussions about it online are just about delineating truth from propaganda.
At some point people do not actually become happier from additional wealth. If you create a system where people are allowed more than that you are just giving them power over vast quantities of resources for no particular reason. It becomes an incentive only for those whose lust for more cannot be satiated and is anti democratic by it’s very nature.