You're expecting the main opposition - the communist party - to beat him then? Zyuganov?
If that fantasy happened it would split the communist party between the half that is controlled opposition who would see it as "the wrong time" for it to happen and the half who truly want socialist power again. The election would then be redone with a 3 way split between the two factions and Navalny's fascist coalition supported by the euro liberals.
I mean, I would want that outcome as it would result in a real left communist opposition emerging but I think it's incredibly unrealistic. Not to mention that you're expecting the population to boot a leader during the middle of a war? I am not sure how often that has happened, populations understand you keep the same leader during wartime. You would need the population to become against the war for that to occur and uhhh I hate to break it to you but absolutely the support the war and it would take a huge change in the frontline situation to change that - one that I do not think is coming judging by the failures of the counter offensive so far.
Oh I apologise I forget sometimes everyone here isn't a marxist now after the reddit waves, marxists would just pick up the intention from context and keeping up with news via parties and groups they're in. The "they" here is generally western aligned think tanks and forces. In particular the Atlantic Council which is largely responsible for a lot of US policy has been pushing it around in the media recently.
A marxist understanding of the war in Ukraine is as a war that was created by the west, led by the US, that benefits quite a significant number of MIC forces with large influence over US policy. Part of the narrative that maintains support for the war is the ongoing belief that Russia can be defeated, and the method of Russian defeated that has been drummed up is "Russia will collapse" as everyone with any sense can see that there is no military means of victory. If the "Russia will collapse" narrative is destroyed by the reality of a rebellion demonstrating massive support that makes any collapse obviously impossible then the entire house of cards that has been constructed falls down. Thus the result is pushing in the media the notion that it wasn't a real rebellion but instead a grand scheme by devious clever russians.
If you have questions about how the left interprets the war I'm happy to answer.