Re: I know this is a big topic on here Iíve been going over it for the last few dats
The mold on the cholla will eventually pass but until it fully absorbs the nutrients present, it will always be prone to return. I can give you other pointers on trying to salvage this setup but I agree with the other posters: cholla wood is not a good choice for warm/moist vivs. I looks cool but it only works, long term, in dry reptile enclosures (ain't no cholla in the jungle).
If you are attached to the cholla in the tank, you can try a heavy rinse (perhaps with a peroxide bath & soak beforehand). This may disrupt/remove the key nutrients allowing the mold to bloom and a different dominant organism might take over. You'll only know if it works after the mold doesn't return - so you need to be prepared to wait.
The right long term solution is no cholla - replace it with manzanita, ghost wood, driftwood or cork. I also agree with replacing the moldy substrate components and then adding some leaves.