>>17857208 (OP)The USSR collapsed in part because of nationalist secessionist movements. Its not guaranteed but quite possible that a democratic Russia would see this go further, especially in the Caucuses, where regions have already been given massive self governance carve outs just to keep them inside Russia.
Russia historically has used aggressive population transfers to ethnically dilute colonized areas because Russia as an empire is pretty infamous for just not offering much material or cultural benefit to peoples it wants to conquer as part of their imperial project. This isn't unique to Russia but it does mean they have had to rely on expensive and time consuming displays of force and heavy handed, growth suppressing political tactics to hold the state together, and as was seen as soon as the USSR lost its grip most of the conquered people that could immediately did run for the exit because they did not identify with Russia and held no affection for it.