There's also drying alcohol as the second ingredient in that activator, that is worse than the silicone IMO. You can add magnesium sulphate (epsom salts) to flaxseed gel for more of a curl boost, but that can be drying so don't overuse it. I would make you recipe super simple initially, if you add multiple ingredients you won't know which works and which does not.
Magnesium Sulfate: Curly Friend or Foe?
Proteins: Why You Should Care
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.