How did it take away national self-determination exactly? The Soviet model regarding self-determination was definitely better than what any other nation had. I probably don't have to mention that Lenin wrote a whole book on national self-determination, defending the right to self-determination on the condition that it does not harm the socialist project.
Although one may call it superficial, a mere formality no indicator of self-determination in the Republic, it is remarkable that the Soviet ruble had 15 local languages printed on the banknote.
My view is that Lenin probably meant well, but he made fatal mistakes with "democratic" centralism and the vanguardist approach, which allowed for both his own consolidation of power but also Stalins. And Stalin did not give a shit about self-determination, not just within the USSR, but within the whole Soviet bloc.
Well, in large part by murdering those that were actually trying to self-determinate...