That for sure. Especially as all the Ukraine resistance fighters would find open borders to e.g. Poland across which they could resupply easily.

However you look at it, this war cannot have a positive outcome for Russia, unless just laying Ukraine to waste is enough for them. This is my greatest fear that complete destruction would be a success for Putin and he would be willing to go all the way to achieve it. Like using nukes.

My big hope though is, especially after withdrawing from quite a lot of regions of the Ukraine already occupied, that after all the losses, the Ukraine together with the supply from the west might be able to hold new offenses from the east and perhaps even push them back. That depends a lot of how many reserves Russia still has and which further weapons they are willing to use.