its hard to discern what would make putin capitulate after years of failure in ukraine, especially since it seems he feels he has nothing personally to lose. these are speculative views from various sources :

- ukraine needs to inflict ~10 to 1 casualty rate to stall\reverse russian forces.
this needs to be in strategic battles, and it seems ~4 to 1 has been more typical, but >100 to 1 has happened in smaller skirmishes.

- more importantly, ukraine needs to exceed hits on russia's strategic infrastructure targets by a decent rate.
genius putin & team has been spending a lot of resources on ukrainian civilian targets...burnishing his resume both as war criminal and NATO strategist!
given the performance, it seems there is no such thing as a russian general being a strategic target.

- russia is now on ~50% war economy and growing, but it seems the public is not that bothered yet, and the oligarchs are not getting less wealthy to notice.