I agree that heat damage generally can't revert and sadly most of it probably will have to go, however since you're cutting it off slowly and not in one big chop, it might be worth trying DC-ing as K.Lee suggested, and also protein treatments (followed up again by a moisturising treatment) to try and get some of the elasticity back.
Products in current rotation:

Terressentials Pure Earth Mud Wash; Elucence MBC (now really just for cowashing, leg shaving or emergencies); Curl Junkie: Repair Me, Deep Fix, Curl Rehab; AOHSR (retiring); Oyin Handmade: Honey Hemp, Hair Dew, J&B; Qhemet Biologics: BRBC (retiring- prefer Oyin HD), AOHC, OHHB; Jojoba Oil for scalp; Castor Oil or Shea butter to seal; Henna & Ayurvedic pastes when I can be bothered.

Still searching for the perfect stylers, but loving CJ CIAB over everything so far