But I gave it a go again and this time I spent time figuring out how to sync between devices. I've yet not synced files but here's what I got so far.
1. Koofr WebDAV for Reading Statistics sync 2. Kobo's built-in sync for progress
Both of these are free. This is a reminder mostly for myself that you need to use the service password for WebDAV access for koofr and not your koofr account's password. And make sure you save your koreader user credentials somewhere.
I'm still not happy with the keyboard situation, the koreader keyboard is ugly but I guess it's optimized for eink so that's something. I don't really type any notes into books. I mostly prefer being able to sync progress and have a centralized view of my reading statistics. And this works.
I copied all my books over manually for now, I'm happy with this. I have the following devices 1. Phone - OnePlus Open 2. eReader - Boox Tab Mini C 3. eReader - Boox Palma 1 4. Samsung Galaxy Tab S9 Ultra
Things I didn't know I needed: 1. The reading statistics. This tracks every eBook I read, and I don't have to use anything else. 2. Book map - Knowing how much time I spent in each chapter is a godsend. This really helps me understand things like this. 3. The speed reading module - perception expander - I'd never heard of this from Tim Ferris so it was new to me. I am giving it a go, and I'm not sure it's improving my reading speed but it feels like it's improving my comprehension!
Thank you to everyone who puts in the work on koreader!