Opinion on various prefabricated house providers desired

No, other providers sometimes have only one drywall board, without wood behind it... so it can definitely be worse. We have discontinued the soundproofing package, our doors are also somewhat better in terms of soundproofing. I'm curious how it will turn out. In 2 months we will know more :D

What is this soundproofing package or what does it include? Does the wall construction or ceiling construction change?

Yes, the wall and ceiling structure change. On the ceiling, panels are added that bring weight and, above all, improve impact sound insulation. From below, the ceiling is suspended with spring rails. Schwörerhaus is the only prefabricated house manufacturer known to me that specifies sound insulation in numbers in the building description. For the soundproof ceiling 41 dB (the smaller the better the value). For the soundproof interior wall 66 dB (the larger the better). This value is on the level of a solid stone, e.g. sand-lime brick.

Except for the topic of soundproofing in the house, but that's my part, I should have booked the soundproofing package back then. Although I don't believe it's the same with other prefabricated houses that have the same wall construction.

The recipes for walls and ceilings differ only marginally across the industry between manufacturer X and Y. In general, the interested "consumer" pays far too little attention to the aspect of construction and places too many hopes on the material. However, when it comes to sound transmission, the devil is much more in the "frictional connection" between components than in the vibration behavior of the transmission chain. Trying to "scare" unwanted effects away with a material battle therefore only works in a pipe dream. Unfortunately, brains are indispensable here. "Dem Inschinör is nix zu schwör" means hard in the sense of complicated to understand, not tons heavy in weight.

but I believe many companies underestimate what they lose when they use bad salespeople or representatives on a commission basis who are only supposed to get preliminary contracts as quickly as possible.

Companies can rely on the fact that their competitors operate with the same "quality" of customer advisor actors and therefore lose nothing insofar as the market share chasing comes back to them in a circle. The carousel keeps turning, but the distance between the sports car and the fire truck remains the same in every round. As long as none of the competitors realize this, nobody loses ;-) But at least someone also wins from this, namely the small construction contractors without their own marketing department. Their practically best salespeople are those of the bling-bling brands, whose dumb and brazen chatter drives customers to where they are helped.

Schwörerhaus is the only prefab house manufacturer I know of that specifies soundproofing in numbers in the building description.

I also saw this at Weberhaus. For exterior and interior walls they are relatively the same, impact sound insulation was better with Schwörerhaus.

Silicone paints are not unproblematic either. They only last a few years, then the silicone is depleted, and the stuff is enormously chemically stable and remains in the soil for centuries. Also extremely UV resistant.

Um, please correct me if I'm wrong, but you probably mean silicate paints? These consist almost entirely of mineral components. Silicone is something completely different again (synthetic polymers) – are they really used in exterior paints?

No, facade paints with silicone additive. Explicitly.