Thanks! Frankly so long as I can get a browser and install some reader apps (Kobo, Manga-one, etc.) that would fit my needs fine, and as long as they support older versions of Android for enough years (or I can avoid upgrading the app version) then things should be fine. The 10.3" Boox is 80k JPY which is a bit pricey, though, but I'll consider it vs the Kobo device next time I upgrade e-readers.
FWIW, I also hear good things about Kobo, though I don't have direct experience.
Those are based on Alpine Linux rather than Android, AFAIU, and if you're into Linux are apparently more readily customised and hacked.
(The fact that BOOX is Android is a misfeature for me, though it does make many more apps available. As noted, I use few of those and could replace much of their functionality with shell or Linux-native GUI tools. I suspect battery management would suffer however.)
