just like in the Empire, no religion was imposed at all:

What about faith, for the Tsar? And Orthodoxy was the dominant religion. And what happened to that Empire? And in the USSR, did no one believe in anything? And atheism is not a religion. A common faith destroyed the Empire, destroyed the USSR.
The Empire was held together only by an external threat. And only victories in wars could strengthen it. Defeats only weakened it. The revolution had already been brewing in the minds of the intelligentsia since the 19th century. But this idea was suppressed and then reintroduced later.
And did the Poles want to be together? Probably, they just dreamed...
And during the civil war, rampant nationalism flared up, which was suppressed by a book by Marx. And all this grew on the yeast of the Empire. The USSR only postponed the inevitable - the collapse of the country. You cannot live on multiculturalism. Sooner or later, it will lead to a collapse.
Religions should be gotten rid of - that's my opinion. A person should cultivate culture within himself, and not have religion dictate to him. Otherwise, it will be as usual: one person believes, forces others to believe, and it all starts... And the whole point is that it is easier to take something ready-made than to cultivate it yourself. Just dangle a golden apple in front of a person...