Welcome! You also need to consider your dew points/ humidity, if you have a smartphone download the free 'Curls on the Go' app. Curl Keeper is very heavy on humectants (glycerin and propylene glycol) so can be wonderful or terrible depending on your hair properties and dew points. Ideally use a leave in conditioner with Curl Keeper, it's not a conditioner.
Protein can strengthen hair and can also boost curl but too much is drying for some, powerful humectants can hold too much water close to hair and weigh it down or can just define they don't usually boost curl. You don't have to go all-or-nothing with protein, just try something gentle/ weak and use a stronger product later if you get good results.
Since you are in Europe a lovely reasonably priced product is Schwarzkopf Gliss (Kur) ultimate volume conditioner: this contains plenty of hydrolysed protein and panthenol, is CG friendly. I get great results from this as a leave in (but start just as wash out conditioner to see how your hair responds) - lots of curl, shine, softness and definition even when used with no styling product.
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.
CO-wash: Inecto coconut
Treatments: Komaza Matani, coconut oil, Hairveda Sitrinillah
Leave in: Fructis Sleek & Shine (old), Gliss ultimate volume, Inecto argan
Styler: Umberto Giannini jelly, Boots Essentials gel
Experimenting with: going back to basics