What you absolutely must also consider - you wrote
"Living on 129.5 sqm with deduction for sloping ceilings, so 170-180 sqm)"
and
"Our idea: 130 sqm living space with 4 rooms + living room + kitchen/bathroom and guest toilet with shower and utility room without basement"
Mentally subtract the sloping ceilings completely from your apartment. Now you don't need the hallway just once (ground floor) but twice (ground floor and upper floor). 5 to 8 sqm of the 130 in the house are gone. So far you have had a utility room outside the apartment. Another 7 to 10 sqm missing in the house floor plan. You might already have a guest toilet but now with an extra shower. You probably also currently have a basement room for storage, which is also extra sqm. That’s quickly 20 sqm missing, maybe even 30!
Compared to the apartment, effectively only 100 to 110 sqm remain in the house. Does the current apartment already have 4 bedrooms? If not, you also need space for the 4th bedroom... so hand on heart: would your apartment with 4 bedrooms, without sloping ceilings and with 20 to 30 sqm less "work"?
That would be a massive deterioration of the living situation with a 130 sqm house—except hopefully it won’t rain inside anymore.
Conclusion: Comparable would be 150 to 160 sqm in the house with the 130 sqm of the apartment. That in turn is roughly 50,000 more than for 130 sqm...