I don't want to speak too soon as my hair is still damp and drying, but I think it's nearly safe to say, problem solved! My hair looks much more defined, the curls are back, bouncy, and still feel soft and healthy! I think my hair loves protein lol. I also just ended up doing the ACV rinse anyway, I was feeling gutsy :P I left the PT in for an hour, rinsed out with plain water a bit, then did the ACV rinse (1 part vinegar, 3 parts water), then conditioned and brushed out as usual, except conditioned with TN Vibrantly Smooth instead of Aussie Moist. It's a nice conditioner! Great slip. I feel like the ACV rinse helped lock in the protein better, and I know for a fact it really helped reduce frizz!

Then I styled, but used much less leave in, only a penny size (still more than enough so I think I could even go less), about the same amount of Curls Rock Amp., and then maybe a loony size each side of my hair of gel, rake then scrunch. I left it to air dry. Looks great ! Thanks so much for the help guys!
Hair Type: 3a/3b, dark brown, blonde highlights, normal - high porosity, fine - medium strands
Low Poo: Live Clean Moisturizing Shampoo (lowpoo)
Condish: Aussie Moist or Tresemee Naturals
Leave In: Giovanni DLI or Garnier Fructis Sleek and Shine LI
Styling: Curls Rock Amplifier, Pantene Curl Defining Mousse (HG)
My hair loves protein!