If your hair isn't too long and you have good water pressure, rye flour can be a really effective shampoo. I understand it sounds kind of kooky but it's ph balanced and gently absorbs excess oil without stripping it from hair. I have thin, fine textured wavy hair that's extremely prone to frizz and I used to walk around looking like I had a Van der Graaf generator in my pocket. I swapped to using rye flour and cut my hair short and now I love that my hair has cohesion to it and it's so so soft. Cons of rye flour would be that it can be hard to rinse out completely and it can make a mess with little flakes left in the shower or on a towel. It's also a bit weird to use because you need to turn it into a sort of paste as you wash, so you can't prepare it beforehand. Anyway, it might be worth a try if you're looking for something gentle, but you might still want to only rinse your hair every other day to avoid stressing it.

Have you tried the "no-poo" method? It's supposed to be pretty good for curly hair.While I'm no expert and don't have hair anywhere near yours, I haven't used shampoo except when getting haircut. I use shea butter conditioner and I generally enjoy it. Just don't get the one they have at Costco. It's a weird mixture and I thought it smelled horrible when they rolled it out. (It has a green pump)

I’ve been really happy with Cantù Shea Butter. I also have 2b/2c. Current routine is shampoo about twice a week, and either conditioner washes or just warm water pretty much daily with this heat. I’ve been using Cantù for a couple years at this point and always regret when I try something else.

I use Aveda for guys. Only thing, it probably will be at the cosmetic store. I like how little I have to use for really good results. My hair is very fine, and I can confirm it is very gentle.

I use Naples solid hair shampoo bars. Very gentle and works well, but I only shampoo my hair maybe 1-2x a month, so I can't say if it is good as a daily shampoo.

Have you tried going longer in between shampoos?