https://brandonjkessler.com/technology/2021/04/26/setup-kobo-sync-in-calibre-web.html

For a kobo you can replace the kindle store with your own calibre library so you can download and read any book you have stored in calibre.

Why would you want that if you can have something light that can be held in one hand?

Try tailscale for remote acess run it as a docker container. I csnt help you with the other questions.

It’s not i’ve bought two of them years ago because they have a decent spec rugged phone. The s60 was bulletproof and lasted ages and even a drop from standing height on concrete. I upgraded to a later model (i think s90) and that was a piece of shit. The quality control is crap, don’t expect software updates but if you get a good one the hardware is great. So not a scam but i would stay away.