Depends how likely Ukraine is to implode at war's end. Do you expect the Azov movement or Right Sector to simply lay down arms and peacefully coexist with ethnically-Russian Ukrainians once the war's over, however it might? Least of all after eight years of war they helped perpetuate (and feeding Putin his precious casus belli), and now that they've been handed all the first-world weaponry and materiel they would ever need? When basically their whole-ass stated goal is to ethnically cleanse Ukraine of Russians?
I keep calling them the next al-Qaeda for a reason.
Considering they number a scant couple of thousand at the very highest
estimates (and even then they were since decimated during the battle of Mariupol, almost certainly leaving them in the hundreds), and they attempted precisely nothing significant on a national scale between Russia's invasion in 2014 and Russia's latest invasion, I'd call this far-fetched, if not intentionally overblown for war propaganda purposes.
I'd be a little more concerned with the fascist paramilitary that has grown
exponentially since the latest Russian invasion began, into the tens of thousands, landing not only official endorsement but also a military tech centre in the capital city; that is deployed to half a dozen conflicts overseas, rather than just defence of their own country's borders, where it has been responsible for numerous ethnic massacres: Wagner. Or the Kadyrovites, who stand as the ruling power in Chechnya, and carry out round-ups and summary execution for gay people. Then we have the fact that destruction of Ukrainian national identity, forced deportation en masse, "filtration camps", and other classic tools of ethnic/cultural "cleansing" have been heartily adopted by the Russian authorities themselves.
Azov and Right Sector are utter footnotes in the shadow of the sheer size, reach, financial/military power, and track record of war criminal activity of Wagner and Kadyrov. But the concern just... well, isn't there, among tankies purportedly invested in combating fascism. Mostly because the denazification angle is mostly a ruse: you can tell by how often figures like Medvedev, or the state media, seamlessly switch from talking about "denazification" to "de-Satanisation" and "de-Ukrainianisation". It's the same thing for them, and it always was.