Depending on your protein powder (casein, pea, whey isolate etc.) there is more or less binding of liquids - I recommend fine tuning it to your liking but this is a pretty thick dough on my end :D
Hm, interesting. I guess oat and coconut flour behave very differently from AP flour? My usual banana bread recipe has a higher dry to wet ingredients ratio than this and it doesn't get anywhere near dough consistency.
Yes! Main benefit is that it result in a much nicer carb to protein ratio. I use a pea and whey blend from time to time. Comes out really nice. But in this scenario I even have to add some water to make the dough not too thick!