Arch is great. You’ve kinda dipped your toes in it with Manjaro already. I recently moved to EndeavourOS with BTRFS for my gaming computer and couldn’t be happier. I could have done stock Arch but I honestly didn’t care enough to. EndeavourOS has great sane defaults and no bloat. And you can pick almost any DE during the install. Spin up a VM and give it a try if you can.
I can’t speak to MATLAB though. But all the others you mentioned I also run.
The only issue I have right now is the half screen flickering with GNOME and NVIDIA drivers. But I just ignore it.
Is this only for music, or tv shows as well? I find myself shuffling shows a lot and it was nice in Plex to have a smart playlist and exclude shows that had been played in the last X days from the playlist.