I don’t know, I used gnome for a while and I just felt like I was using toy apps. But I think that comes down to personal preference. KDE definitly has the bigger apps like Kdenlive and Krita.

Yes, using them is probably the closest one can get to the macos ecosystem on Linux.

Have you checked out Xournal++ already?

The u-he synths are nice.

Reasonable well.

Getting plugins to install is often a big hurdle, if they are working, they work. However I think performance suffers alot. Didn’t try it on any bigger synths yet tho.