If you don’t mind paying for it, Bitwig is probably the best that officially supports Linux. There are also ways to run windows VSTs in wine on Linux. I’m no pro, but I love Bitwig, it has boatloads of cool stuff. Reaper also supports Linux. Ubuntu is fine IMO, I think there is a spin that’s specific to audio workloads that might be nice for a beginner. I use Arch at home but I use Ubuntu for work, it’s pretty nice these days.