Maybe the fatty acids and fatty alcohols are building up in combination with the oils you are also using. Have you tried clarifying or just a week or two on a light CO-wash/ milk type conditioner? Will your hair type not permit detangling in the shower with soaking wet hair coated in conditioner?
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