Also, how's Ukraine war is sustainable for Ukraine? It's economy is non-existent (almost 100% dependent on western donations), it has less than 50% of population of 2022 (they don't publish any population stats directly, but if you combine available statistics, there are about 10-15 millions left most of them old retired people or young people that are too young to send them to the front lines), they are losing territory every day.
This is some weird "Ukraine is winning but front is moving in the wrong direction" logic.
As long as the EU keeps supporting them, I think Ukraine will be better able to maintain the current situation than Russia. But Ukraine is nearly as exhausted as Russia, and I think a European coalition sending real practical ground and air support would help a lot. I suspect sufficient support could force a breakthrough in southern Ukraine an liberate a very large chunk of land very quickly.
The reason that's not happening is either that NATO thinks this would give Putin the excuse he needs for large scale mobilisation, or simply because Europe is afraid to get its hands dirty. I don't think the former is nearly as big an issue as some believe; Putin has never needed any action from NATO or EU members to justify escalation, and has never responded to imagined red lines getting crossed.
The latter is more likely. I think Europe needs to remember the sacrifice that Canada and the US brought to liberate Europe in WW2, and recognise the moral obligation that creates to liberate others in a similar position. Like Ukraine today.