ᐅ Building a Prefabricated House on an Existing Basement/Foundation?

Good evening,
we have purchased a plot of land in a residential area that includes a 50-year-old prefabricated house with an existing basement. Renovating the house is not worthwhile, but if possible, we would like to keep the basement and then build the new prefabricated single-family house on top of it.

However, the footprint of the existing basement is smaller than that of the prefabricated house we want:

Dimensions of the existing basement (floor plan in the attached file):
10.82 m x 8.58 m (35 ft 6 in x 28 ft 2 in), but with an offset, meaning 4.5 m (15 ft) of the width extends 1.20 m (4 ft) at the front, and the remaining approx. 6.3 m (21 ft) of the width extends 1.20 m (4 ft) at the back.
There is also an additional load-bearing wall in the middle across the entire width of the basement.

Dimensions of the prefabricated house:
12.35 m x 9.10 m (40 ft 6 in x 29 ft 10 in)
+ 4.61 m x 1.20 m (15 ft 1 in x 4 ft) (flat-roofed bay)

A direct connection between the basement and the house is not essential for us, as the basement has an external staircase and is primarily intended to be used as storage space.

Is it possible to fully thermally separate the basement and the prefabricated house and possibly place a slab foundation on top of the basement without structural issues?

What costs should we expect at a minimum, assuming the basement is still very load-bearing and the ground conditions are favorable?

Is this approach worthwhile at all, or would it generally be better to build a new basement from scratch?

Of course, any additional suggestions or advice are very welcome.

Best regards,
Dirk