The wound isn’t being give a chance to heal with such regular cleaning with hibiscrub and even occasional licking.
As above hibiscrub shouldn’t be used that often in a healthy wound and I would only be cleaning very gently with warm water if the wound is heavily contaminated at this point. But that should happen if you are covering the wound for walks so try to avoid cleaning as much as possible.
Pop a long sock with some tape on when the dog in unoccupied if likely to lick. Alternatively put a buster collar on.
As for the manuka honey, in recent years there has been research the shows use in healthy wounds, i.e granulating wounds with healing edges that are clean, is contraindicated as it can limit fibro. So actually it could be making things worse and is no longer needed as we are past the debridement and decontamination phase. Quoted Squeak to pass this onto them.
See article below for an understanding on why:
https://veterinary-practice.com/article/manuka-honey-is-it-still-the-bees-knees
Ps. Strange your vets aren’t taking the dog in. We have been for months unless particularly aggressive/nervous/owner must be present.
ETA. As above posters there is no difference in the healing cycle for breeds of dogs. Yes greyhounds are thin skinned (we have a lurched and whippet so get this) but they still heal well.