NATO doesn't have an answer to the Russian invasion. They know they can't go in themselves and directly fight Russians, and they know they can't support Ukraine with billions indefinitely.
Everyone says that giving up Ukrainian territory is absolutely out of the question, but that's what has already happened. Crimea hasn't been Ukrainian territory for 10 years now. International recognition doesn't count for much when the reality on the ground is that the Russians control the region.
I genuinely don't see any outcome where Ukraine gets its territory back.