I have played 2,995 games. I got to 1020 on a lucky streak, but my rating still sits stably at around 900.
There are people who are fast learners. There's someone I met who went from new to 1300 self-taught with no formal coaching, in around a year.
But there are also average people like you and me, who are not blessed with that gift. And it sucks.
I'll be honest, I have no idea how to react to this reality either. It's one of those hard truths we just have to... live with. Some people are born greater than us. You could train your entire life and still be beaten by someone who hasn't trained at all, and that's true for any skill. It's completely unfair.
But I guess all we can do is work with what we've got, right? A lot of people support you, and are improving alongside you. Some faster than you, some slower than you, all wanting to reach quadruple digits.
You're not dumb. I think it's normal for this to happen, especially if you have no formal coaching and are self-taught. That one 1300 guy is the exception, not the rule.
In fact, people who learn fast might not get a sense of accomplishment from reaching such a high rating, since it's so easy for them. They may be harder on themselves when they do make a mistake, because it "SHOULD be easy." Fast learning is a double-edged sword. If you're learning fast, but not feeling a sense of accomplishment when you reach your goal, is the learning even worth it? We, however... We have to work for it. So when we finally reach a stable 1000, we know that we won, even without all those genetic advantages. And it'll feel SO much better.
Don't give up, we're in this together. You've got this.

If chess isn't for me, nothing is. It fits my personality perfectly. If I really am beyond salvage, then I really should [redacted] myself, I'm not going to find something better in life and I have nothing else currently
My Dear friend,
Firstly... PLEASE, don't be hard like that on yourself.
With Chess.com and Lichess put together, I have played something like 600 10+0/10+5 games, but more than 4000 games, adding the other lesser time controls (bullet, blitz). Believe me, they are practice too, as are puzzles.
My rapid rating is only 999 (and very less than that in the other time controls). All that I wanted is to go over 1000, but I can't get myself to play another game, since I am so "close" to 1000. I was feeling horrible about this as well, and there are mean people out there, on FB or other social media groups that will use such thing as an online chess rating to hurt you. I started playing OTB small amateur tournaments (10+2). Every tournament, I do 50 to 60% victories. When the opponents I defeat ask me my online rating, they just can't believe I am only 999 rapid. I say "nine hundreds" and they are listening, pretty naturally "nine-teen hundreds", untill I repeat "zero-nine-zero something".
There is something that happens in online games that doesn't in OTB. I can't tell if it is the visual stuff, the anxiety or whatnot. What I can say is that in these OTB games I am super chill and high spirited, and even when I lose (40 to 50% of the games) I don't feel a bit of "rage" or frustration.
There is no such thing as "chess is not for you". Maybe "professional chess", just as "professional basketball" and "professional football". Professional play is something build, at the most, since early teens. Excepcionally, someone gets great starting later. But the standard is: if one is not started as a kid, it is already too late to ever become a "professional". And guess what? 99.9999% of people playing chess right now ARE NOT even close to any "professional" level. I am fine with this, and you should be as well.
Enjoy life, a life with chess as your beloved game. One day I will go over, or fall from my 999, and the Earth will still be going around the Sun, my wife and cat will still love me. You will still be loved as well, whatever your "online chess rating" is.
Cheers!
Honestly it's probably just being around people