I think with applications, like Calibre its relatively painless to save the whole library, if someone is ready to jump ship. Now its the perfect time.
I personally use a Kobo without the online features, which is fantastic, but there are many great Kindle alternatives without the corporate spyware bullshit.
It absolutely does. https://plugins.calibre-ebook.com/ there is a KFX input plugin. Also, if using an older version of kindle for PC you can batch download your whole library and import to Calibre.