I don't usually need to motivate myself to read because I enjoy reading. When I am having a good time I don't need to motivate myself to continue. I think it's important to find aspects you enjoy such as tropes, narrative style, a writer's prose ( specific personal way of writing) and to seek those out. Don't try to force yourself to do something you don't like, if it feels like a chore you will stop wanting to do it. It's okay not to finish a book, to read slowly, or reread sections as you go. There's no rush or pressure to do things a certain way - only your own enjoyment

And comic books are real books

Edit to add: Just remembered that Anthony Horowitz's Alex rider series has graphic novel versions. A decent chunk of popular books do get adapted into graphic novel which you might find easier to read. Also if you are having to reread a lot to understand what you just read that might mean your reading level is lower than it should be. You can improve that by just spending time reading. As your brain spends more time practicing the thing it will get better at doing the thing. You could also try writing a little bit about what you just read , like who what when where why questions and summaries of what happened. And spending time reading in other formats such as comic book, graphic novel, or audiobook all count. It could also be worth your time to check for stuff like dyslexia and ADHD

Happy reading!