Recommendations for wall surfaces in new construction

Hello everyone,

the question comes up again and again, but the circumstances are always different. That’s why I’m writing here again. Our new building (semi-detached house with basement/ground floor/upper floor/attic) is progressing and currently we are in the planning phase with the drywall installer / painter.
Our exterior walls and load-bearing interior walls consist of sand-lime brick panel elements. The non-load-bearing walls are made of gypsum wallboard and the ceilings are made of concrete.

According to the building description, all rooms except the cellar rooms are prepared in Q2 for textured wallpaper. We recently got a quote from the painter and were quite surprised at what they charge for Q3 and painting.

Therefore, my question now is, what would you have done in the new building or possibly do yourself?
Currently, the plan is to have all the “public” rooms (living room, kitchen, hallway, bathroom, WC) done by professionals and take care of everything else ourselves.

Would you have everything sanded to Q3 or is Q2 enough and then make your own touch-ups? Or is it not worth it in terms of cost / benefit? I’m not dumb, but I’ve never done it before.

If the ceilings are also done in Q3, is fleece still needed?

Certainly, Q3 and fleece is the most optimal (also for settlement cracks), but I would like to save a little at certain points / try it myself.

I would really appreciate a few tips.

Thanks already to you all

The question is how high your standards are. In the basement, you can do that yourself. For example, spraying. But not Q3 as a layperson. I wouldn’t trust myself to putty and sand at Q3. Q4 would be optimal ;) Good materials alone cost money. You can save some money when painting, but not when bringing the substrate to Q3. Just save on the woodchip wallpaper and only paint the wall...

I would always wallpaper rooms that are large and sparsely furnished. Wallpaper also absorbs sound and the rooms don't feel so "echoey".

I'm not that demanding, personally Q2 + wallpaper would be enough for me. (Isn't textured wallpaper "out"?)
Whether Q3 or 4, there is no perfect wall. If you look closely, you always see something.

You can always paint yourself – right?

I recently saw how some family members wallpapered with this painting wallpaper (non-woven). It wasn't a big deal either. The same applies here: work carefully and in the end it's just hard work. For non-woven or well plastered walls, I would also "just" paint as suggested.

Q2 for 3 already takes hours. If two are supposed to be enough, you have to lightly paint the inside with something slightly rough, which masks small dents. Filled primer is suitable for this. Sto has something like that. The method. One person rolls the primer on, the second wipes a pattern into it with the ceiling brush in motions, after drying, possibly another coat of paint on top. That somewhat resembles so-called brush plaster. It is currently architects' favorite.

I have often used brush-on plaster with 1mm quartz sand from the company Haering, great stuff and very economical.
Prime once with ordinary white paint, then apply the brush-on plaster directly with a large brush, e.g. in a cross-stroke, white or tinted as desired. I once used 2mm on the ceiling, which I would not recommend because the sand grains did not spread easily; 1mm looks great in my opinion.
Due to the 1mm grain size, it forgives slight imperfections in the wall plaster.