Man that looks good

I use lithium. The free version has some limitations like not being able change the app to darkmode (although from what I remember the pages of the book itself can be changed to white/sepia/dark even in the free version). It has cross-device progress sync too, but I can't remember if it was there in the free version). Worked well enough for me. Decided to get the pro version after a couple of years cause I had been using it a lot and didn't have any gripes with the app. (Look for it in mobilism if you don't want to pay for the pro version)

More than anything else, I'm going to miss the easy access to reliable answers by appending reddit to whatever I'm searching for in Google