According to The Economist's analysis, Russia has sufficient fiscal reserves to maintain its current posture for at least the next 5 years, which is far longer than Ukraine will be able to hold out.

As for post-Putin Russia, the most likely scenario is a fragmentation into four or five separate states, each ruled by a thuggish overlord devoted to asset-stripping. This would be the ideal outcome for the West, especially as the nuclear weapons that terrify the USA's Appeaser In Chief would decay due to lack of maintenance. As the world is already in full-on proliferation mode thanks to Biden's eternal spinelessness which has taught every tinpot dictator on Earth that Job One is to acquire nuclear weapons, there's no additional risk from the thuggish overlords selling their inherited stockpiles to third parties.

So there's really no downside to a Russian collapse and it's an indication of how inept Western "leaders" and their "advisers" continue to be that everyone wants to maintain the status quo.