I think that Ukraine should begin considering that certain territorial losses to Russia are really and truly unavoidable (Crimea first and foremost, then partially Luhansk and Donetsk). At this moment, territories for peace (be it even a prolonged armistice without a peace treaty) seems like the best options to end this bloody mess.
I mean, let's be honest and face it; for all the Western military aid, Ukraine alone cannot defeat Russia --- the best they can hope for is a prolonged stalemate. The only way that Ukraine can defeat Russia is a strictly conventional WWIII --- ie, there's no way thay can defeat Russia.
I kind of imagine they said the same about North Vietnam and the USA. A prolonged stalemate can play out to one's advantage, if the other side cannot bear the costs. Ukraine can bear the costs, because it's facing an existential threat. It has nothing to lose. Of course, the Vietnam analogy breaks down because then a communist dictatorship was facing a democracy, and (naturally?) the dictatorship won. Apply that refinement to the analogy and, yeah.. time is on Russia's side.
I would however caution about the reasonableness of territory swaps. Personally, I don't mind who gets Crimea: it was wished away by Khrushchev as easily as it was taken back by Putin. Whatever.
The real problem is not the giving or taking of territory. It's the fact that Russia is treaty-bound to respect Ukraine's pre-2014 territorial integriry. It's completely screwed up on that treaty obligation. So what in Heaven's name will make it adhere to, and uphold, another treaty to which it pledges to respect Ukraine's post-2022 territorial integrity?!
It's the breach of trust that's the issue, as Chamberlain found out in March 1939. You don't get to sign treaties and then trounce them on a whim without people suspecting you aren't the kind of guy we want to negotiate another treaty with.