Its only choice is how many of it's kids they want to send into a meatgrinder trying to hold onto the Russian-speaking territories whose people it didn't seem to like very much before the invasion, and it seems to like even less now.

There's no realistic way for Ukraine to push Russia out, let alone deal with the resulting insurgency. Same applies if Russia tried to hold the Ukrainian-majority territories. Actually they're probably in for an insurgency either way given their conduct.