At B1 Level you can understand a lot of texts, if you’re willing to put in the work. You’ll have to look up a lot of words and re-read passages a few times occasionally. It’ll be a bit of a slog, but it’s also the most effective way to improve your reading comprehension. It’s also a lot easier these days when you can just look up stuff online. Back in my day, I’d have a dictionary sitting next to me and if a word wasn’t in there, I’d have to go to the library to look it up in the Biiig Dictionary (OED ftw).