This pompilid wasp flew around in the house. It is a female Agenioideus sericeus  (see also here), a very rare species in the Netherlands. Since my first observation of a female in the garden in 2019 the species is active in the garden every year.
It has not become clear whether there was more than one specimen present this year, presumably there were two.
I caught, photographed and then released her.
References1 Nederlands Soortenregister