I’m trying to get diagnosed atm, so maybe take what I’m saying with a pinch of salt, but I have the same issue. Except, when I’m reading fiction (that I enjoy), I read extremely fast. Without actually using speed-reading techniques (most of which are hokum anyway), I reach about 700wpm, and about 95% comprehension and recall. Stick something totally boring in front of me, or even something interesting, but written in a boring manner, (such as a nice, dense philosophy text), and I can spend an hour trying to read, without even making it through a page.
The best advice I can give you for this type of thing is to do your best to find summaries of whatever the texts are you have to read, then skim the source text for key quotes. I didn’t actually read, cover-to-cover, a single book relating to my field when doing my degree. I couldn’t. I’d rather try to eat rocks (philosophers are REALLY bad at writing in an engaging way). I see you like Wikipedia. Wikipedia is your friend.
The only other thing I can recommend for generic focus is to try doing pomodoros, if you haven’t tried before. Basically, set a timer for 25 minutes, and for those 25 minutes, do your DAMNEDEST to focus on whatever boring task you have to undertake. Don’t check that email, don’t look out the window, don’t grab a snack. If you get PROPERLY distracted (as in, for more than a minute), reset your timer and start again. Then, reward yourself with a 5 min break. Lather, rinse, repeat as needed (but take a longer break after 4 pomodoros). It makes it easier to concentrate by turning the ‘task of indeterminate importance that just has to be done some time before whenever until i get to the end’ into ‘Task that is the ONLY THING I need to do for the next 25 minutes until those 25 minutes are up’. It’s surprisingly effective, at least in my case. I actually wish I’d discovered pomodoros 10 years ago. Would have changed my life.
Hope everything goes well, buddy!