Ukraine has shown and singalled that without help, the lines will be moving in the wrong direction.
If they get their borders back (win), Russia will have a strong argument that the war was with the West, not just Ukraine. And I don’t know that Western politicians have the stomach for that kind of win, because the nuke thing, if nothing else.
The pols may be open to it, but even when there was less push back, I didn’t see the will to win. It was the will to not lose, and then trust Ukraine had what it took.
At this point I think we know that Russia and Ukraine will have a massive generation-size gap in their male populations. And at the end of this, absent significant help, will be a slow war of attrition with Russia moving lines often enough to matter.
Anything short of restoration or either historical border is a loss. At least of land and lives, if not other.