Our construction cost overview - It can also be "affordable"

Everyone as they like it

Not quite. Everyone as they can.
We have almost the same infrastructure as the OP, paying about +/-150€/sqm. This is the Hamburg metropolitan area.
But I also grew up here and have a permanent job here. My profession is a rarity, so hardly any opportunities to look elsewhere.
When I was still commuting to Hamburg (30 km), there were some colleagues who moved 89 km away to an area with cheaper building land.
The result was that at every snowfall or storm/rain at night, people liked to call in sick because it was cumbersome to shovel themselves out of the snow in the middle of nowhere.

Good infrastructure is priceless: rural means for families that mom then plays taxi for the kids, in old age rural can mean loneliness and dependence.

For us, a higher loan for the 150€/sqm for a plot that must be at least 650sqm would be manageable, but it feels like "I don't want to." We decided on leasehold... somehow it comes out to the same, but there wouldn't have been any other plots in our area anyway.

Rural is not the same as rural. That much is certain. I will neither play taxi for my child nor suffer from loneliness in old age. You are right when we really talk about small villages. That can be exhausting at times. But to be honest, I'm also not a fan of putting 4-year-olds on a bus - playing taxi probably belongs to a certain time.

We have nearly the same infrastructure as the OP, paying around €150/sqm. This is the commuter belt of Hamburg.

But that must be a very outer commuter belt. Nothing goes under €200/sqm in the commuter belt I know. Friends already paid €200/sqm in Glinde about 5 years ago.

We built in a village with 2,000 inhabitants, were received fantastically, have a kindergarten and a school within a 3-minute walk, a pharmacy, a doctor, two bakeries (with a mini supermarket) and a sausage and cheese truck twice a week... and at least VDSL.

It is 6 km to my old hometown, i.e. 2 minutes by car, where all the markets etc. are also located.

We probably won’t die lonely (the cemetery is next door, saves a lot on transport costs), but our children will have to use bus, bike & car later. That’s just how it is, won’t kill anyone... almost everyone drives to shop anyway.

But we don’t have a garden where everyone peeks in, didn’t pay 300 euros/m² (6 km further it’s like that if you can even get something), we have a river and looooots of forests/meadows around us.

We both have lived for years in cities like Berlin & Münster, as well as in normal towns, but centrally – never again.

But that must be a very distant commuter belt. Nothing under 200€/sqm goes in the commuter belt I know. Friends already paid 200€/sqm in Glinde about 5 years ago.

I don't like to exaggerate and prefer to add a +
But Lower Saxony is always a bit cheaper. We need 10 minutes by car to reach Hamburg via the highway.
We are directly adjacent to Hamburg with the district – I was once told that most of the economic millionaires from Lower Saxony live here. Work in Hamburg, live on magnificent plots of 3000sqm +
All of our areas are municipality parts with a rural original structure.

...only if the Elbtunnel/-bridge aren't completely closed again
Have a nice weekend everyone!