Protein makes my hair dry out, when my hair is dehydrated it refuses to clump, can go both poufy and straight, it's usually a couple of washes before it recovers a bit. I still do them because my hair is damaged/ porous but I have to follow with a deep treatment. For me coconut oil with sugar syrup (can use honey) is giving me the best curl and bounce.

Maybe try a curl cream or make an Ecostyler custard (gel plus an oil, sometimes plus aloe vera)? These should be sticky yet more hydrating than just gel. Have you tried the Supersoaker Method for clumps?

Vinegar can be drying if used regularly, really what is working is likely the low pH, if that is what your hair responds to maybe look at the pH of your conditioning products instead.
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/ fractionated coconut oils, Hairveda Sitrinillah
Leave in: Fructis Sleek & Shine (old), Gliss Ultimate Volume, various Elvive
Styler: Umberto Giannini jelly, Au Naturale styling gelee
Flour sack towel, pixie diffuse or air dry.
Experimenting with: benign neglect