Interior doors not according to standard

Hello dear people,
I registered here because we (like probably quite a few here) have a "small" problem and are unsure to what extent we are in the right or can take action.
About the problem, from the beginning: We had a 4-row townhouse built, shell construction. The rest (electricity, etc.) was contracted elsewhere or done by ourselves. Everything wonderful. Now it's about the complete interior finishing with floor laying and installing interior doors. With the interior doors, we noticed that the door height is not standard.
In the contract with the construction company it says: "According to plan". In the plan, the basement is 2.17 m, ground floor and upper floor 2.30 m. Without screed (this was added later with 16 cm in the basement/ground floor and 13 cm in the upper floor).
The basement is no problem. There we reach the standard dimension.
Ground floor and upper floor door openings now require custom-made doors.
We never requested such an extreme height, the construction company says they always build it like this and did not point this out to us in advance, during the construction phase our interior doors representative also called the construction company and asked them not to exceed the standard dimension. Unfortunately, due to stress and work, no one paid attention anymore. The plan with these dimensions was also accepted at that time. In writing.
We are aware that we have no leverage to cause a fuss or claim defects. However, we do not find it right that we, as laypeople, were not pointed out to this and although it is not standard, it was sold to us as standard.
Anyone got a tip or maybe has already experienced or heard of what one could possibly do?

Again: We are aware that since the plan was accepted in writing, we have no leverage to officially get upset. However, the doors now cost us almost twice the normal price, or we have additional costs anyway... even if we are still tinkering ourselves to get back to the standard. Very annoying, but hope dies last that maybe I can still officially get upset.

Many thanks in advance.
Best regards!

Are the walls already plastered inside?

If not, then maybe fill the missing piece of the door at the top with expanding foam, cover the front and back with a piece of wood or drywall, and then plaster or something else (wallpaper) over it. It's a bit fiddly, but it should be doable somehow.

Yes, also. We are now at the point where we only have to lay the floor, paint, install doors, and move in. It happened so quickly that we only noticed when we wanted to buy doors.

Basically, I also find higher doors more attractive. Unfortunately, though, it's also a matter of price.

Yes, that's right. And that was not calculated that way. In itself, it's also nice. But just not what was calculated and desired.

Was that a German construction company? Other countries often have different measurements...