Your co-wash conditioner is your shampoo substitute so treat it in a similar way, you wash it off with all the skin cells, sebum and old product.
Given you colour if you choose to low-poo I would suggest you select carefully, looking for a product that is free of all anionic surfactants not just free of sulphates and that is pH 4.5 to 5.5 (acidic). This will be the gentlest it can possibly be on skin and hair.
That means looking for surfactants like cocoamidopropyl betaine or decyl glucoside. There are lists of surfactants in the different 'families' here
Ingredients Commonly Found in Hair Care Products
Actually all the 'curl chemist' articles by Tonya McKay are worth reading as you have time.
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.
Treatments: Komaza protein, Komaza Matani, coconut oil with sugar syrup. Hairveda Sitrinillah
Leave in: Fructis Sleek & Shine (old), Gliss ultimate volume
Styler: Umberto Giannini jelly, Boots curl creme, Rockin RInglets
Experimenting with: Mega-Tek, Curl Harmony reviver, Elvive Full Restore 5.