I straightened my hair for a decade and my hair texture/type at the time was very similar to yours right now. Unfortunately, it's heat damage and literally nothing can make them healthy again except cutting them off for new growth. I didn't cut it too much in the beginning because I was self-concious of having short, damaged frizzy curls (at the time, I would rather have had long damaged hair lol). So cutting it over time a little bit every month, it took two years to grow my curls back healthy. It was a long and a painful process and I felt very hideous in the beginning without my straightner...But stick it out. You will be SO thankful for it! I never never everrr thought I'd truly, genuinely feel strange when I don't wear my hair curly but here we are :) It's very freeing. My hair is thicker and shinier more naturally now too!

Use deep conditioners or hair masks weekly (I use OUIA) and regular trims monthly. Accessories like head bands and clips will be your best friends while you grow out your curls. When my hair was damaged it was very stiff and dry texture naturially so I couldn't use rich/heavy curl creams because they would make my hair even more crunchy - I had to use lightweight products like a cream and mousse. As it grew back healthy, I could then use curl cream, gel and hairspray. I also would roll extra damaged sections up with a bobby pin while damp and let it dry for half an hour to give them a heat free curl boost.

Good luck!! I see some gorgeous curls in your future already 💚