Tiny bulges on wallcoverings made of paper and not vlies/vinyl
putting them up without these is impossible because all random dust is visible

This is false. A wall can be made very nearly perfectly smooth and all but the tiniest of foreign materials can be removed. It is all about the preparation. Wallpaper has been a standard wallcovering for many years and not all jobs have &quot;acne&quot;.
Often, the person paying for the job is just not prepared to pay for what near-perfection costs. Other times, they pay for near-perfection but the contractor is not capable of providing that. Other times, neither party even discusses what their idea of perfection is and expectations for what good looks like are not aligned.
The wallpaper hanging craft is as much art as science, and professional paperhangers employ esoteric methods that most people do not have in their repertoire. If your workers were not part of your local paperhangers' guild or trade union, I would bet they are not wallpaper specialists.