What can replace wood paneling?

Thank you! That wasn't really the plan either. I thought about taking down the wood and attaching new panels like, for example, fiber cement to the battens behind, then plastering and painting. The question would just be what costs I should expect. I thought I could ask here to get an idea of the direction before receiving the painter's quote.

And as for the wood, those were leftovers from a timber dealer that closed down back then. It cost me almost nothing at the time.