ᐅ Plastering and painting work in a prefabricated house performed by the construction company or a painter

We are currently building our prefabricated house. The living area in the basement is approximately 50 m² (540 sq ft). The living area in the upper floors is about 200 m² (2,150 sq ft). It is a prefabricated house on a precast concrete basement.

Our home construction company has offered to finish about 900 - 1000 m² (9,700 - 10,800 sq ft) of wall and ceiling surfaces by

- filling and plastering, then wallpapering with textured wallpaper (Rauhfaser) and painting for €22,000 in Q2,

or alternatively

- filling and plastering, then wallpapering with a painter’s fleece and painting for €40,000 in Q3, except for the 50 m² (540 sq ft) basement living area, which would remain finished with the Q2 method and textured wallpaper.

Are these prices reasonable or too high? Would you recommend hiring the home construction company or a professional painting contractor for this work? We are undecided. Has anyone had similar work done?

The building region is Stuttgart.