Floor in concrete optic / Screed floor

He doesn't have much experience with it, I even suspect none at all. But he knows about it, has brochures on the subject, and can get the materials.

Well, then the most important conditions are met

I find the floor very stylish and don't really like having tiles. Otherwise, we just want to lay parquet. In the hallway, bathrooms, utility room, and stairs, we wanted a concrete look.
In the neighboring town, someone does that quite well. I follow his Insta profile. The results look very stylish..
Surely expensive. I will inquire with him.
But I have a master painter in my immediate family who feels confident to do it and would actually do it for free. We would only have to pay for the material. However, he doesn't have much experience with it, I even suspect none at all. But he knows about it, has brochures about it, and has access to the material. That's why I don't know how we should decide.

Well, that's the question. Technically he can do a lot, including plastering, he also has colleagues and can obtain information/devices. I believe he has already done stairs. The question is whether it's witchcraft? It's clear that a hobby craftsman shouldn't do it. There is also a painter in the neighborhood who offers it.