So depending on what you want to build, the house price doesn't have to be that far off. We had 198k on the contract (bungalow, without basement, 180sqm, without SmartHome). It ended up being about 230k with upgrades and we had to add more for the roof. SmartHome can also be kept cheap. We built with one of the classic "budget providers." Everything went great, but it basically required me to act as the construction manager – which suited my control freak tendencies very well.
Regarding your costs. They seem fine to me. Daycare costs will drop later (do you have contribution-free years?), but then there may be costs for the OGS (still factor those in). These are usually between 100 and 200 euros. On the other hand, hobbies get more expensive and the first pet wishes start coming in. Salary increases will also come. Initially, our financing was rather tight and now gets easier every year (less maintenance, salary increases, daycare cheaper thanks to over 2 years old, etc.). What you shouldn’t underestimate, however, is the money that goes into the garden. You’ll bury one or two money trees there.