If you are willing to pay kagi is great.

Yes! Audiobookshelf is great!

I switched because Microsoft just keeps getting worse and worse, and I like having complete control over my system. And limiting the amount of my data going out.

Linux in general uses much less system resources than windows, and I like being able to easily change my workflow (desktop environment, window manager, etc).

Do it! Linux is great, and not nearly as hard as its reputation suggests.