My music owning experience in life has been a story of jumping from one monolith to another. It started with iTunes. Buy from the store or rip a CD, all in iTunes and then synced to device. Then it was Spotify and a variety of other streaming services.
Now you have every single analogue/anti-algorithm/minimalist yelling, buy an iPod! Own your own music. And to be clear, I am absolutely one of those people. But wow, it's a rough experience to switch. Once you have all of the music it should be easy, in theory. I have a few thousand songs on my hard drive.
The metadata and file organization are all very weird depending on where you got the music from and how you imported it. So you're going to spend quite a bit of time managing that. Getting the music is pretty annoying too.
The last bastion of one-stop-shop is iTunes. You can indeed buy music there. The cloud locker service -- iTunes match -- still exists for $30/yr. But the default Apple Music app has gotten bloated and it's very pushy to get you to subscribe to streaming. I haven't tried to install Apple Music on linux but there's no support by default which isn't a great sign.
Bandcamp is fantastic, but the library of options is really limited. Qobuz has an iTunes sized library but the interface is absolute garbage and doesn't let you stream the music you own from their site.
I think this would all be fine but we're missing a killer *just music listening* app. Rhythmbox for Linux feels promising but it's not very feature complete and the external device syncing has been rough in my experience.
This is a bit of ramble, but I guess I'm surprised at how difficult the process of "I give you money, I put music on my device" is. It feels like we're full circle back to the reason the iPod was invented in 2001.