Dream house possible with our financial means?

Maybe my house data will help (year of construction: 2015/2016; region: Upper Bavaria - same region as OP); costs without land, garage and additional construction costs:

Custom-designed single-family house; brick
215 m² living space + basement (almost 100 m²)
Biomass heating
Controlled residential ventilation
Large window areas (including 6.4 m long corner glazing; floor-to-ceiling --> complex statics)
High-quality interior doors (> 800 €/each)
Oak parquet (complete - except basement and bathroom)
Two bathrooms (tiles; including 60x120 cm, 100x100 cm)
21 linear meters built-in wardrobes; room-high (planning: interior designer; manufacture: carpenter)
Wood stove (Brunner)
Kitchen (carpenter)
Raffstores everywhere including control
Front door with fingerprint sensor
High-quality door communication
High-quality lights and lamps (> 13,000 €)

=> just over 510,000 €

Recommendation:

Forget wind turbine
Storage (these are kWh, not kW!) --> then with integration of control power + heat pump; ROI after 15 to 18 years (without subsidies and energy price increase)
Exterior facilities (1,000 m²?): Ugly if the garden doesn’t match the house because the budget ran out --> minimum 20,000 € (with own work!)
KNX – for those who need it...
KFW 40: air heat pump; tends to be somewhat cheaper and “sufficient” with this standard

I think it will work with your budget.

We are building with an architect, a custom-designed, solid house (2 full floors with a pitched roof). Not a catalog house from a home construction company.

KNX 20k? Never... that is absolutely unrealistic. With KNX you need: KNX planning (KNX specialists... we used a KNX planning office). It cost us about 4000 EUR including drawings. Tip: START absolutely very, very early... KNX affects EVERY trade. We made many mistakes there. Then you need the hardware... for us about 20,000 EUR and the software. I am doing this part myself, so the only cost is for ETS (1000 EUR license). If you let someone else do it... you can also expect around 15,000 EUR here. I completely underestimated the complexity and am glad about the construction stop (weather & frost) to gain some time. The 1300-page book (Amazon: Home Automation with KNX, DALI, 1-Wire, and Co) unfortunately only touches on all topics superficially. But it’s a start. You definitely have to be really into this. Well... and finally, you need the classic electrical work (pulling cables, etc.). For us that’s about 15,000 EUR. So in total for KNX + electrical work we land at about 40,000 EUR. Without own effort (software) it would be 55,000. Our neighbors ended up spending about 80,000 EUR. They have about 280 sqm living space.

20k you can definitely forget about

A different question: where can you get a plot of land in Ingolstadt for 150-200€ per m²?? That seems unrealistic to me.