This is from when I was using Linux full-time around 2010, but I was a foobar2000 user on Windows and wound up using Quod Libet as the best Linux-side replacement for it I could find. It wasn't a perfect substitute, but it worked for my needs.
(Some searching suggests that DeaDBeeF might be an even closer match these days, but it was brand new and I didn't hear about it back then.)
The tooling back then was so good for windows desktop though. Before the recent mess. It enabled a lot of really nice apps. Good example of what great dev support can do for a platform.
I agree that Paint.NET and Foobar2k are the two things I miss when I moved away from Windows. Amarok is a nice iTunes replacement for Linux, but it's no Foobar.
People use foorbar in different ways, but when I moved (foorbar works well in Wine btw), I discovered that Quodlibet is actually a better version of what I was using foobar for.
Inkscape certainly has some idiosyncracies in its UI, but yeah, for the most part it's very reasonable and mostly adheres to common UI/UX conventions. Not sure how much it deviates from, say, Illustrator, as I haven't used the latter.
some software can't be replaced and don't have good enough alternatives, and prevent me from switch to linux
windows is getting worse, but not bad enough to justify me switching to linux, exactly because of those softwares
it's odd in a way, because the free software for windows is generally higher in quality that the one I find on linux.
And Gimp will never replace paint.net. Inkscape also have a very difficult UI.