Kindle alternatives?

So I am looking at alternative ereaders for when my kindle eventually dies due amazons continuing draconian hostilities towards users.

I know if I can get the same book for the same price at any other store (kobo or google play) since I can back up my copies there to calibre and my ABS server (along with my audio book purchases).

I like having complete control over what I purchase. I may still keep KU if only for whispersync pricing. But I know those are rebels per the subscription and can’t be backed up anyways. I go though 8-10 KU titles a month and will often buy them if I really like them.

Unfortunately so many titles I like especially in the science fiction, fantasy scene are locked into the Amazon ecosystem. Perfect example Dungeon Crawler Carl.

So I am looking at alternatives

Wants:

Lots of storage (32 – 64 GB+)

Easily able to transfer files aka side load all my prior books via calibre on my pc

Long battery life

Nice to have

Color screen

Support for other reader apps (KU is still a thing, not mandatory since I still have my phone or laptop)