There are many different scalp complaints, and mild moderate and severe forms which can look quite different, even have different symptoms in different people. If you do not have seborrhoeic dermatitis (greasy dandruff, caused by a yeast) you do not need a medicated shampoo at all, in fact that can worsen other scalp complaints. If it returns please get a formal diagnosis rather than blindly amateur treating.
Many of us use our rinse out conditioner as a leave in conditioner. How much you need depends on your hair, I am porous so needs loads of leave in conditioner.
2a-2c, medium texture, porous/ colour treated. Three years CG, growing out mechanical and chemical damage = breakage and very high porosity. Past armpit length heading for waist.
CO-wash: Inecto coconut
Treatments: Komaza Matani, coconut oil, Hairveda Sitrinillah
Leave in: Fructis Sleek & Shine (old), Gliss ultimate volume, Inecto argan
Styler: Umberto Giannini jelly, Boots Essentials gel
Experimenting with: going back to basics