Russia's mutinous mercenary chief Yevgeny Prigozhin was shown in a video on Wednesday welcoming his fighters to Belarus, telling them they would take no further part in the Ukraine war for now but ordering them to gather their strength for Africa.
He runs his own private army with a ton of loyalists. That's not as easy to push out a window and Putin knows it. On top of that, I wouldn't doubt for a minute that Putin at some level agrees with his complaints of Shoigu and Gerasimov.
And unfortunately Putin encouraged Wagner to be funded by all sorts of black market, crypto enabled activity. The Kremlin can't just flip the off switch on them, because there isn't one.