Highly porous hair benefits from protein treatments, followed immediately by a deep treatment.

You could try Curl Junkie Repair me, which is a good protein treatment, and follow up with Curl Junkie Rehab (no, I don't work for the company LOL).

There are probably equally good drugstore versions - I just happen to like the CJ products a lot. I don't know about mayo - I do think it may make the shower very slippery so watch out if you use that.

A few protein/deep treatments will help a lot. Good luck and let us know how you are doing.
2/c and some 3A.
Protein sensitive but can use occasionally
Highly porous. Color over grey.
Best 1st day method: Super Soaker
Stylers: Mix Curls in a Bottle into everything for shine. Terrible pj
Sometimes try roller sets - classic glamor but I prefer my curls.
Every day is a gift