Shampoo doesn't moisturise (add or increase water) it cleanses, and most products damage the hair even if only in a minor way. It's your conditioners that should be moisturising if your hair needs more water - with CG you would be using three (rinse out, leave in, deep). If you ask one product to do two jobs you often end up with a product that does not perform well at either task.

If you want the gentlest possible cleansing go for conditioner-only washing or a shampoo at pH 4.5 to 5.5 AND based on a glucoside or betaine surfactant.
2a-2c, medium texture, porous/ colour treated. Three years CG. Past bra strap length heading for waist.

CO-wash: Inecto coconut/ Elvive Volume Collagen
Treatments: Komaza Care Matani, coconut/ sweet almond oils, Hairveda Sitrinillah
Leave in: Fructis Sleek & Shine (old), Gliss Ultimate Volume, various Elvive
Styler: Umberto Giannini jelly, Boots Essentials gel
Flour sack towel, pixie diffuse or air dry.
Experimenting with: benign neglect