Feedback floor plan - size and price ok?

So for me, 500,000 including incidental construction costs and high-quality equipment was enough.

What do you want to say with that? That it can basically work or that the budget planning discussed here could be accurate?

Nothing presentable has come out so far. If there is interest, I would keep you updated...

Of course, definitely!!
As a tip, even if you haven't had the best experiences with architects so far, don't draw too much in advance and if you do, leave it at home. If you show that to an architect, they might just trace it.
How do you want to proceed now anyway? Start over, okay, but with the same architect? New architect?

Simplify and reduce the floor plan. The above-mentioned carport also saves a few euros - even if it's probably just the gate.

So for me, 500,000,- including additional construction costs and high-quality equipment was enough.

-200 sqm living area
-solid construction
-no basement
-2 full floors
-hip roof
-including a brick carport for 33k
-in central Hesse
-own work: 0

the whole thing on a plot with a height difference of 2.8m over 29m

But then still without landscaping and kitchen/furnishings. Landscaping is really a big item on a sloping plot. We're noticing that ourselves right now. You can't just pay that on the side, and with the mandatory estimated 25k you don't get far on a slope either. But I find such orientations quite good.

We will probably end up at around 630k (God, that's crazy) including additional construction costs and landscaping. For 240 sqm on a slope + a masonry garage 6.2x9.20 built into the slope but next to the house (so not within the thermal envelope), with a roof terrace on the garage, normal to slightly upscale equipment (i.e. geothermal drilling, large-area parquet, partly raffstores otherwise electric shutters, 2 lift-and-slide elements each 3m, expensive canopy, large-format tiles, a bit of smart home, glass railing on stairs and gallery). Then the plot and kitchen or other furnishings are still missing. Own work: partially retaining walls in the garden, paving, laying floors, partially painting, setting interior doors.

Correct, and also doesn't have a basement that would be developed as a separate apartment with living quality like the OP's = 80sqm difference.

Also, if he already built ("500k was enough"), the contract was at least from when? 2018? 17? So rather 2000,-/sqm = 400k plus additional construction costs, so 500k in total is more realistic, but they also have almost nothing in common with the floor plan presented here.

The 500,000 euros include EVERYTHING except for the outdoor area (however including the retaining wall costing 13,000) and of course the land! So really including furnishings and kitchen. Even carpets, lamps, decorations and similar things are included. : I want to say that as a guideline and with a budget of 450k for the house, you can certainly get something decent. The first thing I would cut would be the granny flat, gallery and such gimmicks. Nevertheless, with this budget the house can definitely be designed generously. I probably have DIY work worth about 1000 euros in the house. So if someone is handy or has friends willing to build who can do it, you can certainly save a few thousand euros here and there. Also, my fittings are certainly rather higher-end (parquet on 160 sqm, bathrooms fully tiled, dining room lamp around 2,000, lead crystal washbasin around 1800, and other little things). I didn’t want to say more than that. I just wanted to maybe give the OP a little hope.

Single-family house 150sqm * 2,200 = 330,000 Basement (usable area only) = 70,000 Garage = 30,000 Outdoor facilities = 20,000 Incidental construction costs = 40,000 Sum = 490,000 We round up 10% buffer to 550k.

That's exactly how we are doing it too. The numbers fit very well. We have 150x2200=330,000 +Basement 50,000 +Carport 15,000 +Incidental construction costs 50,000 +Buffer and come to a total of roughly 500k€ for a standard house +bay window +dormer +basement. Important: Only sandy soil with minimal slope – with the ground conditions you have, I would add at least 50k€! I would not describe such a slope as "light." Sounds all really bad, but I too have had quite a few teeth pulled here in the forum and the budget was constantly adjusted upwards. But you don't have to lie to yourself and with realistic financial planning you can sleep well at night.