Why it’s important to know your limit? If your improvement is legit, then you are an exceptional chess talent and you may become a world champion one day.
I also improve fast, taking an average it will be around 150 per year (I played chess for some time then quit then came back around 2 years ago).
I’m also an adult who is busy with work and family and I can play only during the night or sometimes in rest time at work, not most efficient times of my life, and I watch videos (if I have courage) only right before sleep. It means there is no dedication, I don’t know if dedication helps for my case, but it’s not important for me (chess won’t make me rich, just fills some of my gaps).
I don’t know about rapid, my rapid is around 2300 but I stopped playing after facing multiple consecutive cheaters. But about blitz, I think breaking 2200 ice was the most difficult one for me. By breaking 2200 I mean staying well above 2200 comfortably, not hitting 2200, and then tilting. The main difference with lower ratings (for me) was that I had to have a decent knowledge of openings and it took me time to gain some knowledge. I was stuck in 1500-1600 for a long time, then I started to watch some videos and after that for me from around 1600 to 2000 (and hitting 2100) happened in approximately 2 yrs, but reaching to 2200 took another 2 yrs, reaching 2300 another year (again by reaching I don’t mean hitting, I hit 2300 a year ago, but currently I’m there comfortably).
Your progress is too fast, more than 1k in 2 years, that’s unbelievably fast, even for kids it is maybe impossible (e.g. 12 yr old GM played chess for at least 6 years, if the starting point is 1200, it means averaging 230 points a year, much less than 500+). Just continue. You could be a very exceptional case.
Ever since I picked up chess, it didn't take much for my playing strength to increase. All I had to do was play some games, watch some YouTube, and wait for a set amount of time... and then whoosh! I'm suddenly stronger by 100 elo points. I never even knew what it was that got better in my game ─ I just started beating opponents I struggled with previously and that's it. The improvement just... happened. And it still does! The only thing that changed from my beginner days is the amount of time that it takes for my rating to jump by 100 points ─ it used to take only a few days, then a week, then a couple of weeks, and now it takes about 1-2 months. But the process is exactly the same ─ I don't need to do much to get better.
The problem is, it can't go on like this forever. For example, I'm pretty sure there are no or close to no grandmasters who started playing chess as adults, and I started playing at age 20, which means that I will probably never get to grandmaster-strength. So my question to higher-rated players for whom this process of natural improvement has stopped is: when did it stop for you? When can I realistically expect it to stop for me? And once it has stopped, what will I have to do to get even better? Furthermore, what do you think the absolute upper bound is on when I will reach my equilibrium point, and what will it take to have a chance of reaching that upper bound?
For reference, at the time of posting, my rating is 2200 on chess.com, and I have never played rated OTB.