as others have mentioned the battery health thing is what makes phones difficult. im comfortable working on phones though so i usually offer them to people like “i have a pixel 3a sitting around that you can have for the cost of a battery”. ive also got a 2nd gen kindle laying around that needs a new battery. considering hacking in a smaller cell if i have one. old ereaders usually cant connect to their servers anymore but that doesnt stop you from putting drm free epubs on them over usb
i’ll never give amazon a single dollar for ebooks but i source tech for a lot of people who arent used to there being alternatives yet or think its still pretty difficult