Trying to escape the Amazon enshittification, I have started to buy ebooks directly from the authors, or from more "reasonable" ebook shops. It's way less convenient, but at least I own those epub files instead of renting them.
I still use a Kindle Oasis, but at least it takes epubs now.
@doppioslash do you have any reference for some of the more reasonable ebook retailers, for when the authors don't sell books themselves?
@ScatteredRay "reasonable" here is code for either DRM-free or DRM-"solvable", shall we say.
Many self-published fiction and non-fiction authors sell DRM-free directly, you should look on the author website and check if they sell directly. Many publishers of programming books (e.g. Manning) do that too.
I've bought some fiction and programming books on ebooks.com, and I was able to get them working on Kindle, but beware that it requires some DRM-"solving"

@ScatteredRay @doppioslash Kobo.com has a lot of books and it lists the type of DRM (including DRM-free) and you can just download the books you have bought

this was the best of the bigger marketplaces I could find (for fiction books at least)

small issues: can't download all at once and each downloaded file has a big ID string as filename so might need to manually rename

no clue about their practices in regards to pricing/monetization in general though