Ukraine is pretty solidly pushing the Russians back, and have a pretty strong nationalist identity, a big part of which is being pissed at Russia. As the aggrieved party, I think they will push until they get to their original borders, or until Russia starts winning again.
They have the people to sustain this level of fighting, and the west seems like it's going to keep them armed, conversely Russia is low on troops and munitions. There's also the fact that the Ukraine has a decent core of Vetern professional troops, still and Russia is running out of conscripts and going to 4th tier replacements.
On top of all that, there seems to be a bunch of "Ukrainian" soldiers that seem to have Ft. Bragg addresses. It's wierd.
All that said, Russia could pull a miracle out and start advancing again, or hold the line till winter when freezing Germans and Poles cause the NATO munitions support to dry up.