Independence movements existed, but they still exist in Russia today in places like Yakutia, Tuva, and, yes, even Chechnya. When the Soviets collapse, people openly wondered how far the collapse would go, and if places like Tuva would break away as well. Chechnya tried, but the Russians forced them back in. Russia won't have the power or stomach for something like that again if it starts breaking up again.
Chechnya is about the only place its possible because they have some smoldering independence, but again, the people currently at the reins have been so completely bought & sold they have no interest in rocking the boat - their people are being used as cannon fodder, but not their friends/family. They are in complete control, the Russian security services operate to keep any threats to their power in check. Oligarch crumbs keep them living large.
Who cares if the people live in hovels as long as you live in a mansion with servants, and have power with no credible threats to topple you? Why would you rock that boat for "independence"?
Main issue Chechnya has is they are too small and no international senpai to support them.
The Baltics (aka the other, bad slavs) were sick of being second class citizens and had been rabble rousing for independence (and occasionally getting something close) for generations. Tuva has been cucked to Moscow since there was a Tsar.
Again, the other places/ethnicities would need functional, viable independence movements before they could hope to have leaders who aren't buck broken moscow simps. Unless it is an external entity imposing terms, you are several long steps away from the Russian Federation fragmenting.
Which, going back to the original point: That's why anyone positing an internally sourced Russian Federation break up is talking crazy talk, huffing high-potency cope. The only way whoever is in charge of Russia loses control is if they abused the various other leaders badly enough to make them consider other alternatives. As long the KGB - its still the fucking KGB just with a different name - is operating and dealing with any threats to loyalist leaders harshly, those leaders will simp for Moscow because doing so keeps them in power.
Even if Total Muscovite Death happens in Ukraine, Even if Putin Strokes out tomorrow, the KGB's operations won't be affected.
A power apparatus that is largely tied to Putin and Putin alone, and otherwise is rife with corruption and barely functional. Nazi Germany would have faced the same problem had Hitler won World War II but died later. The entire state apparatus was tied to his persona alone, not necessarily the office of Fuhrer, and Hitler went out of his way to create overlapping responsibility and pit organizations against each other to ensure that he alone would be the center of the state. Putin largely operates the same way. And just like Hitler, he has no clear successor. Everyone around him is merely a yesman and a patsy. So when he dies, chaos will erupt just because there will be no clear heir to his legacy and everybody hates everybody else.
Hitler is a bad example because Hitler was largely incompetent but used his charisma to surround himself with competent people and then keep them at each other's throats. Additionally the people he surrounded himself with were Germans who have a permanent hard hardon for rigid, clear hierarchy. If he had prevailed in WWII (at least as far as the bounds of "controlling Continental Europe + bare minimum depleting the USSR to a non-threat") such that he would have died of natural-enough causes and a successor needed found, there would have been some Halls of Power skullduggery between the main three. Military High Command would have sided with whoever came out on top.
Putin has no sure successor - Though by no means a sure thing I'd argue Medvedev has probably the strongest claim to the throne, and given he's prove himself a loyal simp who was a puppet the top slot for a while and then quietly handed it back with no complaints, so the Oligarchs will back but his ascension. And unlike Hitler all of Putin's inner circle are incompetent yesmen. But while Medvedev tries to grab the brass from any other challengers, all the state bureaucracies will continue to headed by the same people currently running them. They will shamble along just fine without Putin.