I just asked my new hair dresser who happened to lose hair to the point of having full bald spots after suffering from long-Covid. This is what she told me helped her hair to grow.
1. Use only luke-warm water to wash and rinse your shampoo out very quickly after applying it. Do not leave it in your hair for too long. Do not shampoo more than every other day-- that is even a lot. Use very mild shampoo-- I am using Vanicream for allergies and she seemed to think that was fine.
2. If you can take supplements, collagen and b-complex vitamins are very helpful.
3. Rub a very, very small amount of coconut oil into your scalp (she even leaves it in without washing it out). This will stimulate the hair follicles and promote new growth.

Losing your hair is such a bummer. After going through illnesses I have lost a lot of hair. I am trying her suggestions though admittedly, I cannot take collagen. But her advice does seem to be helping!