^^ What Sirtel writes ^^
The current firmware version runs on a N905C touch and even without patches it's pretty good Firmware using a version of Linux. It integrates well with Calibre for metadata, transferring ebooks, exporting reading status, position, bookmarks, highlights and annotations.
https://pgaskin.net/KoboStuff/kobofirmware.html
The main limitation is the older eink screen.
An eink screen and the HW isn't much use for anything other than ebooks. I have an ereader with a nice custom Android (and Playstore can be turned on), but read almost everything on a Kobo.
I've had/have other makes too.