At least in the EU there are plenty of alternatives. Big book retailers often have an ebook download shop as well as publishers running their own ebook stores. Google Play books, iBooks and others are also around, although much smaller than Amazon. Ironically it's mostly the indie authors that are only on Amazon because they made it "easy".
CaptJack
joined 1 year ago
VLC is usually pretty good with ignoring all dvd region coding, same for makemkv. You could try using one of those to get around the region lock of your drive, if you have not done that yet.