If you allow background processing of shaders, and leave steam running while your doing other stuff a bit. You won’t even notice them. At least I don’t.

I truly wish jellyfin was even close to plex. I’d love to use the open source option. I run a jellyfin server along with plex, but have so many issues with it + the UI is worse. As for the emailing people what you watch. It should have been opt out, but its really easy to turn off in settings. Also I like the plex logins going through their servers. It adds more security to the port I have open. If their server goes down(which is really rare) I don’t lose access to my media because I have at least 3 other ways to access my server. Including jellyfin. Which I use tailscale to access so I dont have the port open.

For your music problem look into running a plex media server and using plex amp to play the music. It may not be super practical if you don’t have a selfhosting setup. But its so far above anything else I have tried. Plus I can steam to my phone as well.

I wanted to like it. It looked so good. But I could only get about a hour into it, and did not like it sadly. I’m sure it gets better, but I couldn’t get there.