@kdfrawg Amazon can't delete anything from your local file system. There have been cases where they deleted books from users' Kindles, but it's been a while.
I now buy epubs from Google or Kobo, and immediately import them into Calibre, which puts them in my Calibre library. My Calibre library is mirrored to a third-party cloud site, so everything is nicely backed up.
Then I convert to Kindle format for side-loading to my Kindle, with a few tweaks to suit my personal preferences.
/@hazardwarning