This is going to give Ukraine a lot of breathing room. Not only does it take Wagner Group out of the picture, but Putin is going to bed to devote already thinly stretched military resources to try and contain a coup.
Long-term, this could be troubling. As fascist as Putin is, Prigozhin is a straight up Nazi. Russia somehow pushing even further to the right is a scary thought. Hopefully Prigozhin and Putin soften each other up enough to allow more progressive elements to consolidate power, but I'm not holding my breath.
I hope the infight between Putin and Prigozhin is nasty enough that the Freedom of Russia Legion and Russian Volunteer Corps can give them both a run for their money.
Prigo will never galvanize the same support and control that Putin has.
This is a good thing for russia. People may actually be able to fight back. It's easier for the oppressed to fight back when the nation's military is split between Putin and Wagner.
It's significantly easier when the propaganda machine loses its poster-child.
Your scenario does not contemplate the crippled economy, with the oil spigot to Europe turned way down, as well as all other continuing sanctions and embargos, which is turning russia into an economic vassal of Beijing as we speak.