No stress, it's not as bad as it seems. For me and my wife, this is also completely new territory; with all these terms, it's easy to get confused.
Forums like this one are, in my view, meant for exchanging ideas, getting tips from those who have had good or less good experiences, and sharing your own experiences with others.
But blindly relying on every recommendation is not a good idea. You should question the answers and find the best way for yourself from the various possibilities.
In this case, it's about the idea of painting wet rooms with a wipeable paint that handles moisture well. For that, we need to see how it looks on [Kalk-Zementputz Q2] or if we should apply [Renoviervlies] on the walls beforehand.