do you have layers? I was beginning to feel, to a degree, what you are feeling. My hair is mid back and layers were long gone. I added a bunch back in and it made a huge difference. I don't know your climate but when winter started here I had to use double the leave-in or use a thicker, richer one. Anyway, only you can decide if the curls are worth the effort for you - I understand how frustrating it can get. I just double checked how long you've been doing this...it took me 15 months to get to a point where I had more good days than bad though I didn't know my hair properties for much of that time (then after i figured it all out winter and long hair happened lol). Good luck to you as you figure out where you want to go from here with your hair.
remember, with all advice or suggestions for your hair, YMMV!!
2b wavy, medium texture, low porosity, med-high density. Protein finicky.
Cleansing: DCNP, every 4-5 days (occasionally use CJ cleansers).
RO: CJSC, occasionally use JCDC
LI: KCKT or CJSL
Gel: KCCC, CJCIAB for 2nd day hair (sometimes third)
Heat is my friend: warm water rinses, steam caps, and diffuse dry. I love CLU cloths and my Denman.