/diy/ - Do It Yourself

So... I had this. And I need ways to fix it.

Long story short, I had a poopy water leak (pipes are inside this thing), and I had to rip drywall.
Now I think about it, what alternative materials I can use there?
>cement board?
>EPS foam insulation + acrylic texture finish
>Plywood
>Tongue and Groove wood
I don't want to use drywall, since it is too messy to remove in case of leak