As you mentioned, there are plenty of other threads that detail ways to improve and different "regimens" to follow, so I won't regurgitate those here. However, I'll leave you with some advice that helped me recently:
Stop caring about improvement, ranks, and beating old scores.
Let me explain a little bit. Improvement and progress are both kind of non-issues that get made into a big deal all the time - for good reason, no doubt. After all, if we want to play harder maps we have to improve first. Then it becomes a measurement problem, where you need something to quantify how good you are, which would be ranks in this case. Another possible quantifiable stat to look at is previous PBs on different maps. Both of these give you a decent enough way of seeing progress, but they also are the worst thing to look at.
Instead of worrying about beating old scores and reaching new levels, just continue playing with some good mindset and you'll see progress. That means: Understand that some days you will play better, some days you will play worse, some days you have to dedicate to boring practice of skillsets or just in general, and that progress won't come overnight. And you might say that your issue is exceptional, and that being "stuck" at the same level for 2 months shouldn't happen. It shouldn't happen, ideally, but in my case I plateaued multiple times for upwards of 5-6 month periods. Yes, I was playing consistently and even training ridiculously hard. So basically, you're not alone in this issue, but it's not something that can't be solved.
I'd highly recommend that you take a look at some of the other "can't improve" threads here in the forums and read some of the advice other players have left, as it generally helps. Keep in mind though that you might have to do things that sound boring like take breaks, practice specific skills, learn new patterns or try new things, etc. Chances are if you have not found improvement you likely have something in your skills holding you back. Whether or not you enjoy that specific thing, you'll have to bite the bullet and practice it anyways.
Tl;dr: If you stop caring about ranks and improvement, you'll forget about them and be surprised and happy when they actually come.
