Wallpaper or plaster? Which is better in new construction?

It doesn't have to be that expensive. There's painter's fleece with 150g/m² for 1 €/m² at the big river. You can also skip the primer, so just paint directly. Buy painting tools at Action. Then you won't have to rinse rollers anymore but just take a new one every time.

But yes, sanding and painting directly is definitely cheaper. However, it probably won't look that good with an amateur.

A simple painter's fleece also doesn't cover structurally critical cracks anymore.

For amateurs, it's better to use an orbital sander. It takes longer, but the result is better. You'll need it for the corners anyway. Drywall sanders are too unwieldy and as an inexperienced user, you're more likely to make dents.

Construction floodlights are also useful for working in the dark. I would not necessarily do spotlights. The risk of going crazy and becoming dissatisfied is too great.

It doesn't have to be that expensive. They sell painter's fleece with 150g/m² for 1 €/m² at the big river. You can probably skip the ceiling too, so just paint directly.
Buy painting tools at Action. Then you don't rinse out rollers anymore, you just use a new one every time.

But yes, sanding and painting directly is certainly cheaper. However, for amateurs it probably doesn’t look that good.

Painter’s fleece also doesn’t cover structurally concerning cracks anymore.

For amateurs, better to use an orbital sander. It takes longer, but the result is better. You’ll need it anyway for the corners.
Drywall sanders are too unwieldy and as an inexperienced person you’re more likely to make dents.

Well, the painter will of course show me. I used a hand sander on a wall in the HAR... I don’t want to do that over 500m².
I would rather say that with an orbital sander I make more dents because I always have to go on the ladder and only sand small areas at a time.
This quickly leads to "Oh, sanded too much, then I have to go over it again here. Oh damn, too much again, then take some off there..." and suddenly you’ve sanded down to the masonry.

It’s like in the kitchen. The amateur thinks with a big knife he’s more likely to cut his fingers, but it’s just the opposite. The smaller the knife, the bigger the danger.

1 €/m² for 500m² is already 500 €, plus adhesive. As someone who has put up a lot of woodchip wallpaper and even occasionally fleece, I also don’t believe it’s significantly easier... at least not if you want the fleece to look really good. And it’s time-consuming. Paste the wall, hang the wallpaper, align properly, cut, press seams well. The corners, reveals, etc.

My opinion:
Anyone who can’t get the wall sanded well won’t get it "perfect" with painter’s fleece either.

It doesn't have to be that expensive. At the big store, there's painter's fleece with 150g/m² for 1 €/m². You can mostly skip the ceiling too, so just paint directly.

Oh, so... Walls at Q3, where anyway cupboards etc. will stand in front, but the ceiling, preferably a filigree ceiling, just paint, no filling and sanding? :D
I've seen that at friends' places, even textured roller plaster doesn't hide the transitions between the concrete slabs...

Then you might as well just paint on Q2, if you don't care about the ceilings ;)

The thing with the knives is true. But now just imagine you had to fillet a fish with a machete. Someone who is practiced at that can do it and possibly even better than with a fillet knife. Someone who isn’t practiced at it will tear the fish apart and after 100 fish will have tendon sheath inflammation.

Yes, well, I have done all that and thus have the comparison. The result with the drywall sander was much worse. That was because the thing is simply too heavy and bulky. And the larger surface area, from which you expect an advantage, turns out to be a disadvantage because you get much more friction and the sanding pad slips away from you. Then you hit your knuckles against the wall. On the ceiling it's still okay since you can apply the pressure exactly perpendicular. But after 100m² you are exhausted. After the first round upstairs, I then used a random orbital sander. It worked better, but if you’re not careful you can quickly make a dent. A finishing sander is just the easiest to control.

Ceiling, preferably a filigree ceiling, only paint, no filling and sanding? :D
I’ve seen that at acquaintances, even rolled plaster doesn’t mask the joints between the concrete slabs...

Was confusing, sorry. No, the idea was to omit fleece. You still have to sand once and fill the joints. For some general contractors/subcontractors the joints are already filled.

Another advantage of the handy device: battery-powered ones are cheaper and with a battery you are much faster on the move. By the way, with a painter's ladder you don't always have to climb down...