Because YOU find that inappropriate? Because YOU don't trust others to inform themselves and then make an appropriate decision on their own?
That's why you are massively exaggerating (fireplace = sauna)?
If I had only listened to the forum here, I wouldn't have a fireplace either. And I would lose a lot of quality of life.
You do know that it could be put differently. If I spoke like that to people at work, no one would take me seriously...
The perfect house is usually built the 2nd or 3rd time. You can only inform yourself as well as possible and rely on experts. And I still assume that a trained professional with many years of experience usually knows more than a builder who had the house or fireplace built by a professional. Making a long drama out of this is not exactly constructive.
We are no longer in the planning phase but in the execution phase. Of course, hints on what to pay attention to can be mentioned. But we will neither want nor be able to change the whole house or the ordered fireplace.
Sorry if you feel offended. You should better accept the matter of being taken seriously for yourself in the future. At times I and other users have a different view of you. For example, anyone who believes that their plot with 20 m width and 75 m depth would be worth over 500 thousand euros (in Fichtenwalde) should especially work on their wording. I see your view on 6 drying units the same way. I will spare further examples.
That you trust your experts may be true, but it does not necessarily suffice in every case. Especially experienced professionals, e.g. your fireplace builder or others, unfortunately do not always have to be up to date. The reference to "we have always done it that way" is often typical. There is a big difference whether 7 kW are installed in a building in 2000 or 2022.
I still wish you pleasant hours at the fireplace. Indeed, that can be quality of life (if the room temperatures fit).