So, if you've got the population involved, I could believe that you could do an uprising with small arms, sure.

But this isn't "the Russian public is pissed to the point of fighting", but "some people in Wagner are pissed". Wagner's got military-trained people, but they aren't that big.

https://en.wikipedia.org/wiki/Wagner_Group

Largest number there was 50K, and I don't think that they're anywhere near that big any more, because they don't have convicts on short-term contracts any more. I think I remember seeing something like 5k in Belarus. Some Wagner people are in Africa or elsewhere. My impression is that the Kremlin wanted them out of Russia as an independent organization -- the people there had to sign on with the military, and I assume that they probably dispersed those. So, a lot of that isn't an internal threat.

I think that they weren't likely to pull off the first march if it came to a serious fight, and that was before a significant portion of the organization was dismantled, and people who agreed with them, like Surovikin, were removed. What was notable then was that a lot of the people in the public, local Russian military, didn't really care, weren't aiming to resist, and they had some level of support from the public, so maybe they could have just rolled into Moscow in some sort of a coup situation and supported that. But if their patrons are gone, I assume that that cannot happen either.

My guess is that if Putin is at risk, it's more because now he's more-dependent now on the military, and maybe someone in the military could perform a coup. He doesn't have Wagner as an independent force to play off against them. Lots of countries have leaders that have been deposed by the military if military leaders think that they can get a better deal with the leader gone.