Earlier quoted context omitted.
I had the same problem and I was able to solve it by timeboxing reading as if it was work, even though it's a hobby. I get comfy, but on some ambient music, and set my little desk timer to about 40 minutes. It's set to not beep when time runs out. I'll start reading, and for the first 20 minutes or so I'll still feel kind of antsy and keep looking at the clock, but 9/10 times I end up finally getting engrossed in wha…
great if you're capable of timeboxing otherwise. not all of us are exactly that... mechanical.
I wasn't trying to prescribe that everyone do this, I just tend to post the methods I've come up with to deal with my ADHD because sometimes it helps people. Obviously it won't work for everyone, which is why I only used "I" statements in my original comment.