Personally i dont kind the shop-focus too intrusive on my Aura HD. I do say, it's fairly impressive that an almost 9 year old device is still getting updates, features, & optimization. There were some really quiet years for updates but the Kobo team has been very active making updates, and many of them are real QoL wins.

Ill try the arduino shops for batteries. My battery died two months ago. I have a new motherboard/battery coming, but I'd love to figure out how to source variously sized lipos.

I havent yet done much futzing in Linux, but definitely interested. Also a shout out to the integrated Pocket reader, which has been a major major win for me, makes the device much more useful to me.