Collections paid and my score is still low, what's next?

Hey guys!

So a little background into my credit journey. After years of lack of financial/credit knowledge, severe mental health struggles, and being young and dumb, we end up about a year and a half ago with three major credit cards in collections, a personal loan in collections, a car that was repossessed and reclaimed, and a 430 credit score.

My car getting repossessed was the wake up call I needed. After getting my car back, I dedicated all my time and extra money into getting everything paid off. All of my collections have been paid off and taken off my credit report (except for one Transworld collections from a $150 tmobile bill my ex screwed me on and I said "let them come take it" ((they did))). Since all my other accounts were closed, I opened two new credit card accounts with Capital One about 6 months ago and I have a credit limit of a whopping $800 (but hey, you have to start again somewhere). They're paid off in full every month!

Today, my score on credit karma says 630! And it feels like such a big accomplishment! So here's my problem. I decided to ask Capital One for a credit line increase, just to see what they would say. When they pulled my score, it said it was a 521! Now, I know credit karma isn't the most accurate, but i didn't expect it to be off by over 100 points either.

I guess my biggest question is, what next? Is there anything else I can do to help my credit. I'm not super interested in disputing everything negative, because it's not like it isn't true, i was definetly delinquent. But I guess I just thought my credit would be higher after paying off thousands of dollars of collections and being consistent on my payments for well over a year now. Any advice would be super appreciated! Thank you in advance!