The USSR famously subsidized and gave autonomy to the non Russian SSRs. Russofication was obviously a problem but much less of a problem than during the monarchy or the post union capitalist state. There is a reason why the non Russian SSRs voted at higher rates than the Russian SSR to stay in the USSR during the referendum before the illegitimate dissolution of the soviet union.
https://www.marxists.org/reference/archive/stalin/works/1920/11/13.htm
China famously exempted all ethnic minorities from the one child policy.