I have inattentive type, so reading for me has also been really hard. I’ll “read” a paragraph only to realize I have no idea what it said haha. Sometimes I’d even have to go over it more than twice .. bleh 😛
My advice is to go as slow as you need to. With books, atleast for me, it doesn’t take long before I can start to visualize the content, and it can kinda take off, until my brain decides to go “Hey! Guess what? You’re visualizing!” and then that derails it. So if your book has little paragraph sections per topic or something, you can just read one, take a sec, process the info, let it soak in, then move on to the next.
I’m the same where I can’t find quite the right focus I need to read as much as I wanna, even though its improved loads. I think it’s all about baby steps with stuff and work your way up sorta. “I made it through a paragraph! I can do another.” or “I made it through a paragraph — SQUIRREL!” naw 😛 — but yeah, pace yourself and it’ll get easier.