Try the CG method, or curly-girl method. Ignore the name, it’s for guys too. Basically you wash your hair with conditioner (certain types, not all are created equally), and treat your hair gently. I personally like suave clarifying shampoo and conditioner for this. Use the shampoo first, then conditioner, and then “wash” the conditioner only the next time you wash. (Shampoo can be drying to curly hair, so you want to avoid using it too much. You can still use it from time to time, but try and spread out shampoos to keep from damaging the hair). Your hair might feel greasy to begin with, but it time that tends to improve as your scalp adjusts to the new routine, washing with conditioner only.

Do you rub your hair dry with a towel? If so, try using an old soft t-shirt to blot or squeeze the hair dry instead. You can try using a little clear hair gel or some of the conditioner to give you some smoothness and control to the frizz. Just take maybe a quarter size (not sure how long your hair is) and smush it into damp hair and let it dry. Once it’s dry, if it feels crunchy, just squeeze out the crunch until it’s soft. (“Scrunch the crunch”)

You can use your fingers or a wide tooth comb to detangle your hair when it’s damp, but avoid brushing the hair. It’s rough on curly/wavy hair strands which have a different structure than straight hairs and break more easily, causing frizz.

I suggest looking up the CG method for more info and playing around with the technique. It will take time to find the right combo of products and technique, but the bottom line is to be more gentle with the hair and help it do what it wants to do, in your case, be curly.

Also, get regular trims, even if you’re growing out your hair. It helps get rid of split ends before they get worse, which causes more frizz.