I don't buy drm crap, genesis all the way, I don't give a fuck, someone needs to come up with a better business model.
https://likebook.aliexpress.com/store/3333002
Looks like they have newer and probably better versions now.
I use Calibre to organise the books (and convert formats if necessary) and push them to the device.
I backup the entire collection using a USB backup drive irregularly (once a month or so). I'm experimenting with Syncthing to backup to a rented baremetal server. So far so good.
Its bookreader, Neoreader, is quite good.
The devices themselves are Android tablets, with an e-ink display. You can install and use any other Android ebook software, including among those, Koboreader, PocketBook, and FBReader.
My preference among those is actually Onyx's reader, at least on their own devices.
A dictionary is a feature I'd love to see added.