The solution being proposed here is exactly the same 'solution' that was tried in 2014. You can't negotiate a lasting peace with Putin. He'll just start all over again after a few years.
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Ukraine doesn't need to win this war. It 'only' needs to ensure that Russia holding internationally recognised Ukraine territory, continues to cause a steady supply of dead Russians. Like Afghan fighters continued to inflict losses on Russian troops in their country.
Occupying territory only counts as a win (for Russia) if there isn't an ongoing cost in dead soldiers attached.
Do that long enough, and Russians (public & industrial / economic / political elite) will get fed up enough that "remove mr. Putin from power" will be the obvious fix. And when that occurs, anything may happen. Including Russia withdrawing from occupied territory.
How about not recognition of that land lost but accept NATO expand its territories covered to the remaining part of the Ukraine.
The problem is what if Ukraine like Turkey did something not agreeable by its NATO Members then e.g. to recover what is theirs.
But without NATO membership, the push to peace is just a stepping stone for Russia to get another piece then another piece then another piece of Ukraine land. The logic will always apply until there is no more Ukraine land.
After all, the Russia strategy to use arms not politics to take over and if successful, where is the end to this. I am not sure this wishful thinking can help.
For the longer term, I mean really long term after the death of Putin (unless cloning of emperor is viable), that is when the problem can be solved?