Ongoing operating ancillary costs single-family house

I would consider the 150€ for electricity from quite reasonable. If the heating is set correctly, no heating element switches on, and even if it runs for an hour, it is negligible. Property tax would be 25€, a real bargain. We don’t live in the wealthy suburbs and pay 600€ per year. For waste disposal, check the website of the company responsible for it. There are different models. We have a base fee, then charges depending on whether the bin is 60, 120, or 240 liters, a separate bio bin, extra fees for more than the allocated collections, and credits if less was used, a DIN A5 sheet with a table. 40€ per month is quite a lot though.

Do you really think that 400 euros/month is enough? For a 160 sqm house and 3 people, I would have guessed rather 600 - 700.

Additional costs do not grow linearly with the living area. 80L of trash is 80L of trash... whether for 2 or 4 people.
The same applies to water. Electricity a bit more. The multiplier for property tax depends on the area.

As says: don't get hung up on side issues, calculate your house construction, it's difficult enough!

350-400€ per month for a new build <200sqm single-family house should be roughly accurate. Most positions are poorly comparable because they vary regionally (and have to be determined/estimated by yourself).

From my perspective: Water possibly a bit low if it is supposed to include wastewater and stormwater. Waste is way too high, we pay 12€ -> varies regionally. Street cleaning/winter service is missing, as long as the city provides that there. Property tax rather too low, but that can only be guessed. The calculation method is completely non-transparent. Chimney sweep is okay if applicable. Insurance much too high. Here with elemental and glass coverage 380€ per year. New builds have big bonuses. But it also depends on the region, whether it is a flood zone etc. Electricity only for household electricity rather a bit high, but you can estimate that yourself based on your consumption. Gas also rather high. Repairs, reserves, ... everyone has to decide for themselves. In my opinion it is unnecessary to build reserves at the beginning when you are still on a wild field. The money first goes into the "final construction". After that you can see further. However, it also depends on your own liquidity whether you want to save something like that separately or not. Dead capital and such.

Think very differently too, but with 3-400€ you are definitely on the safe side.

For us it is per year (if I don’t forget anything):
200€ electricity/heating
200€ building insurance
600€ water
160€ garbage
400€ internet
90€ household insurance
350€ property tax
60€ chimney sweep
Netflix, mobile phone, etc. I’m not including here.
That makes: 2060€
Or: 170€/month

Additionally, maybe 100€-150€/month should be calculated as maintenance reserves.
That would be about 300€

For us, it is per year (if I don't forget anything):
200€ electricity/heating

200€ electricity? Per year? Or is that only the electricity for heating?

have a photovoltaic system

Lumpi, with or without storage? Not that I have to lower my estimate for additional costs