I had Kindle unlimited for awhile, but didn't find many books that I truly enjoyed, unless they were quite old. Many books were self published authors (nothing wrong with that) who would put their books on for some period on Kindle unlimited because it improved their rankings. Some self published books are great, but too many were not. I am a picky reader.
Hoopla, available both for computer and devices via an app, works with your library card to give you access to ebooks, videos (movies, tv shows) and other content for free. It works really well for me and is intuitive and easy to use. Plus, free.