RedReader really focuses on being able to read text. You can set font sizes on every aspect of postings and comments to exactly what you desire for the size of screen tablet/smartphone you have.
Redreader user here too. I find it incredible how it's hardly mentioned when people talk about unofficial reddit apps. It's perhaps the one that maximizes having lots of functions, being lightweight, and being easy to use.
Redreader is a beast. It might not look very fancy but it's one of the most functional clients I've ever used. I saw someone had modified redreader to display lemmy communities on r/apihackathon and the RR dev seemed interested! So fingers crossed :)