Remove in Q2 (drywall) - possible?

One can, we have tried it and it looks good, paint well-cleaned q2 walls with Sto Sil. Sto Sil is a silicate plaster base, slightly grainy, quite thick. You paint it with a roller, a second person goes into the fresh white slurry with a ceiling brush and makes large arcs in it. Make wide sweeping motions. This masks unevenness and gives a nice texture to the wall. Sto Sil, when dry, can be painted over again with any dispersion paint if white is undesirable. Karsten

Only paint over Q2, that is visible. That does not work well. You cannot skip priming either. At least 2 coats of paint are also necessary. Better to apply more thin layers than to slop on thick ones. Good brushes and good rollers save a lot of time and effort.

Good luck, Gabriele