I'm kinda in a similar situation. I'm not sold on e-ink readers. But i dont like lcd screens either
. Then I read that oled screens have better black and conserves energy better, but e-ink batteries still lasts longer. So an oled tablet with 4:3 aspect ratio would be perfect for me. But then oled screen tablets are rare and 4:3 doesn't even exist.
Right now I have an oled tablet in 16:10. In batterie saving mode and only reading, it lasts me about a week. And I put an anti glare protection, so it almost rivals an e-ink reader with more flexibility. It just needs to be in 4:3.