I agree that you probably need both. I have the exact same issue - my hair is dry, and needs moisture, but it is also fine and porous (and has some chemical damage, not sure if that applies to you). Snaps immediately on the stretch test. But since protein can help hair to hold on to moisture (link re this below) I have decided to proceed with using protein, especially because other people with hair like ours have said it has helped. It makes sense to me that if you're using something like Jessicurl WDT (which is really moisturising) and not protein, and the hair is still dry, it may need some protein to help it take advantage of moisturising products. I'm still looking into how the stretch test relates to this, but maybe the snapping is a sign of dryness, but in some cases it is dryness made worse by needing protein to help us hold on to moisture?

THE NATURAL HAVEN: Moisture Issue: Proteins and moisture levels!
UK based wavy

Mostly waves, but curls and straight bits too!
Fine to medium, high porosity, medium density, very low elasticity
Highlights damage (growing it out), seems to like protein and need lots of moisture.

Cleanse - CJDF, trying out low poos ; Co wash- Uk chemist brands, Urtekram Rose or Aloe, Hairveda Amala Cream Rinse; RO - varies, Tigi Moisture Maniac, Desert Essence Coconut ; Leave in - Keracare natural textures; Sealant - argan oil
Trying out new things, still looking.