I’d like to add that the drive to promote local cultures was in large part formal, but very, very influential. I can talk about its repercussions in culture, for example.
Every national republic (and, note, all the Soviet republics were markedly NATIONAL republics, formed as a reflection of their ehtnic and cultural identity and ostensibly out of respect for such) was provided their own program for development of national culture.
Building or rebuilding this national ethnic culture was mandatory, and every republic was expected to institute local ethnic ensembles, orchestras, dancing troupes, theaters, and most importantly film studios that would create uniquely national, ethnic content, to preserve and promote their ethnic culture.
In practical terms, this meant that every republic, even small ones, could expect to have their own subsidied philarmony, a well-funded main national dancing and music ensemble, a national theatre, and a national film studio. These created employment opportunities both for just creative professionals and local ethnic culture enthusiasts. Their output was not consistent, but they were never out of work: the proclaimed support for ethnic cultures of the USSR meant that every national holiday or foreign visit, all of the republics had to send in their best (dancing troupes, orchestras, ethnic bands, performers etc.) to the capital to perform as a demonstration of the Friendship of the Nations (the core concept of the Soviet Union).
Also printing and editing houses, music schools, and museums got a lot of work out of it: they were obliged to regularly publish new compilations of ethnic songs, folklore, and other material, and develop the official ethnic culture in other ways. As for ethnic film studios, they made movies about the respective culture to the best of their abilities, some badly, some brilliantly. For example, Georgian cinema very quickly became its own idiosyncratic phenomenon for the film history books (I mean it, their cinema is georgeous), and, e. g. Buryatian national cinema remained a local curiosity (my own father was a prominent Buryatian film director, and not a bad one - I saw several of his movies and they’re proficient). Another weird example is the Moldovan national cinema: an enterprising director Emil Lotyanu (actually Lototskyi, an Ukrainian) who wasn’t actually ethnic Moldovan filmed an EXTREMELY popular drama about Moldovan gypsies there, with kickass songs, beautiful production design, and sexy leads, which cemented his place as THE Moldovan director for all time and launched a few Union-wide careers (like Sophia Rotaru, who is still popular in Russia).
All of this had a very mixed effect on the culture of constituent ethnicities of USSR. On one hand, it was a kind of celebration of their culture. On the other, the mandatory and restrictive nature of the government request for this ethnic culture also made it formal and stripped it of actual real ethnographic truth.
Even the Russian culture suffered the same fate. Every Russian song got shortened in popular reprintings and performances to 3-4 verses — even though most actual classic Russian folk songs last for dozens of verses. But this real ethnographic practice didn’t fit the official concert format. So the extra verses were cut. This led to songs that are basically meaningless: for example, a song “A lone birch stood in a field” is actually about a maid married off to an unloved older husband, with a long description of a pagan ritual of breaking an cutting birch branches and making flutes out of them, and then going to the house and offering various improper things to a husband to use, to mock him. And also a long circle dance song (so a performative song for a ritual). But the couple of verses you could actually hear in concerts and on Soviet TV and radio never told you that, you just knew that it’s a rather sad song about a birch that someone had broken. It literally lost all its meaning. And this was considered preserving ethnic culture. Similar things happened with non-Russian ethnic cultures in USSR: generously funded, supported, but only formally. Next article: 202005151928 Part 5 - Soviet union