Painting work in new construction by own effort

Yes, you are right, all walls will be plastered by the developer in Q2.

According to the developer, the walls will then be ready for wallpapering.
I assume that I will have to plaster and sand over them again to possibly remove some bumps or small holes.

I know that the house settles over time and cracks may form as a result.
I was just so surprised that the developer said that very many cracks would appear everywhere.

A few cracks like @[B] would not be a problem, but if the whole wall is full of small cracks, then it will no longer look nice.

When it comes to cost savings and DIY work, I immediately thought of Q2 and painter's fleece. You will even find some users here who have directly painted on Q2 and are satisfied. Of course, it ultimately depends on quality differences, because Q2 is not always the same Q2, the same applies to Q3/Q4...

From my point of view, this is the most sensible and cost-effective option when it comes to DIY work and "smooth walls," because rolled plaster, etc., is really not for everyone. By the way, good painter's fleece can also be obtained cheaply on classifieds and the like, and anyone willing can apply it. Then just paint it in any color and you’re done. Alternatively, there is even painter's fleece with different surface textures, which also look very good and conceal additional small unevenness in the plaster...

Apart from that, you will have to take a sander in your hand for a few hours with Q2 to remove the mentioned fine unevenness and pimples. Everything is doable, good, and inexpensive.

maybe you misunderstood me.

it's not about turning every last cent five times over

it's mainly about having a good final result for the next, let's say, five years

we want to do the painting ourselves because a painter for a 150sqm house would like to charge 10-20k or more
if you do it yourself, you get by with about 2-3k

i’m not afraid to spend a few days filling and sanding, only the result should be good in the end and not have many cracks after just a few months (a few would be okay and normal but not an extreme amount)

with wallpapering (but it was Raufaser) we did not have good experiences because you could always see the seams (maybe it was also the wallpaper)

Then you may have misunderstood us/me. At least, it was not about the "cheapest result" for me either, but rather about a good to very good result at an affordable price ;)

You will be able to achieve this easily on your own with a little sanding, painter's fleece (with or without texture), and painting. You just have to start, and with the appropriate will and quality standards, you can have a good result. Start wallpapering first in the utility room, storage room... children’s room and do the living room and co. last ;)

By the way, with painter's fleece it is important that the seams do not overlap, but rather a small gap is left. The professionals also fill this gap with a joint filler and you can no longer see anything. I myself was even able to wallpaper the ceilings easily with painter's fleece for the first time, no problem! You just have to want it and get started...

You just have to want it and get started ...

And be able to...

In 9 out of 10 cases, it usually won't work the first time.

Surely you have some acquaintance/relative who can support you and who knows how it works, or even better, is a painter.

so you would definitely recommend painter's fleece? just fill over it beforehand and sand it relatively smooth and then put painter's fleece on? is there a brand of painter's fleece that you can recommend? filler is absolutely no problem, we have plenty of that no, we don't have any acquaintances or relatives who are painters otherwise I wouldn't be asking here :D