Hi all! I posted this in 4a too, but I suspect I'm a little 4b as well, so maybe one of you has the golden answer for my woes

Okay, so I've tried to find threads that deal with this, but I'm (desperately) hoping someone can shed some more light on this for me:
I have the most insanely undefined roots in the history of the galaxy. No really, I checked the whole galaxy.
I'm 4a (I believe) and can get great definition at the ends of my hair, but the roots just won't curl, even though they obviously want to. I've tried to apply more product to the roots. I've tried raking, which works for the rest of my hair, but not the roots. I've tried gels, ACV rinse, finger-coiling, etc. I even stopped using a comb to detangle for a while and just using my fingers to preserve definition. Seems like I've done all I can think to do
A little more background: I don't have any straight hair at the ends; I've been fully natural for years now. I do have much heat damage, but if it were that, wouldn't it also affect the ends too? Also, I'm not using cones and I generally co-wash, and do a non-SLS shampoo weekly (I still haven't figured out how to make my Shea mix feel less thick, so I get paranoid about it coating my hair). I don't use heat anymore (as of 1.5 months ago), and I DT 1-2 times a week. I henna (well, cassia) and use oils and Shea. Oh, and I don't use terrycloth, only microfiber. And I wrap my hair at night. Sorry for rambling; I just want to give as much detail as possible
Does anyone else have this problem? Should I just be using a ton of conditioner? Maybe I have a hair twin reading this who can help me
I posted pictures below. TIA!!!!!
By the way, in these pictures my hair is soaking wet (I know, it sure doesn't look like it)!!