Like what other evidence are you looking for?

government documents decreeing bans on minority languages and cultures

Again i am not saying there wasn't russification and that it wasn't a huge thing that the soviet union tried to push

You're not going to find some official documents stating such and such thing was ordered.

why though, every racist regime ever has such things

racist governments have racist laws and decrees, thats what makes it racist. Like i can easily bring up the time the soviet government forced the mongolians to adopt acrylic text in teachings. There could easily be such evidence if it exists for banning of ukraine language.

I don't expect you to take my word for it even though I lived through it both in Ukraine and Poland.

unless you are 50 you did not live through the soviet bloc, which is what im talking about specifically. I will not dispute the policies of imperial and modern russia.

Most of it is going to be written history of people who lived through it.

Not trying to discard them, the soviets did things wrong, but you cannot base it purely off of anecdotal evidence.