The current Crimean population is in any case no more Ukrainian than Russian. So given the historical context and current situation, any conquest of the Ukraine would be more of a catastrophy for the current inhabitants than remaining in the Russian Federation. Basically, just like in Donbas, I expect more traumatised and displaced people from giving these territories back to the Ukraine than letting it being part of Russia. Probably some Crimeans would even prefer independence, probably that would even be a 2nd best solution to the problem, who knows. But bringing them back under the control of the current Selenski regime, is for sure nothing "nice" to do these people. Its also drastically against vital Russian interests, which brings me to the conclusion there is no sort of moral or humane argument for bringing them back, even less by force, under Ukrainian control.
This is one of the instances when the people from Democracy Now made a valuable analysis of the geostrategical situation:
https://www.youtube.com/watch?v=EzotonmeTn0
Just like I said, better make peace soon, better take negotiations serious and don't start the 3rd World War. I have to add: I hope so much that the European leaders stay strong and oppose the American and some Eastern European warmongers and make their desire clear, that they want to build the Russians a diplomatic bridge to peace. I know the Americans and some Eastern Europeans, especially the Poles, will press hard for taking even more aggressive and hostile measures against Russia, and to prevent any peaceful, diplomatic solution from happening. But as much I do hope that the European leaders which are at least somewhat more reasonable than the American cowboys block this and don't let themselves dragged into this catastrophy.
Don't start World War III for the American warmonger.