Eh, I'd probably leave music off that list. Even mainstream music releases are still pretty easy to buy DRM-free via services like Qobuz, even if the majority of people are using streaming platforms these days. Although I wonder if that's maybe just because music seems like it would be pretty easy to sidestep DRM, even if they do come up with some kind of innovation (heck, even my friend told me he pirated my album... WHICH IS FREE, BTW).
But e-books? Holy crap the drm on those things is soooooo annoying to avoid.