I’m sorry I should read more English literature, but I’m a bit in a hurry right now.

1. You shouldn’t feel guilty if you haven’t given them a cent since they’ve been exposed as Nazis (and as a rapist in Monson’s case), and if you haven’t listened to any new release, i.e. if you don’t contribute to their careers now. You may have done this in the past, even by normalizing them, but that’s all you can do right now, and at the same time the bare minimum.
2. Should you feel allowed to get emotional on a Nazi’s music? Cold rationality may make us stray away from humanity when we touch this topic, honestly; I’m all for rationally discussing Nazism, but ambivalent people really need to understand that a Nazi is de facto a monster first, and that they’d be so much more useful dead than alive that it outweighs the usual considerations on their dignity as a human being. Now, yes, if it helped you keep pushing back then, if you don’t fund their careers and if you don’t listen to new releases.
3. As a reminder, you may self-host a private tracker on an old computer that won’t boot Windows 10 for you and your friends, complimented by a Jellyseerr/Sonarr/Readarr setup. Anyone with a bit on experience in piracy has a few high-quality discographies, so maybe one of your friends has downloaded their discographies on TPB back when they were “controversial”.
4. As a semi-related reminder, the IRC protocol is designed for asking questions. Linux distributions (and other standard operating systems) have the best compatibility; interestingly enough the protocol has kept one third of its user base since its peak, and the Undertale’s Undernet is actually the name of one of its oldest servers. You’re probably gonna need help with your first server so feel free to come around and ask questions.