Interior doors not according to standard

Yes. German company. And also has a good reputation. Asked several companies and it was also the only company that made us a decent offer. However, they build such heights "as standard." I find it really crappy that a professional company does not point out that the door dimensions are outside the standard. When they build turnkey, they source their doors from a carpenter. (That has now become apparent.) But we had already thought that maybe a neighboring country might have that as a standard. Nothing.

I understand correctly that after the screed you still have a door opening height of 2.17m? Minus floor covering 1cm? = 2.16m. With standard doors of 2.10m it could almost fit with the frame. I just measured, with us it is 2.15m including the frame. Otherwise, slightly plaster over as already mentioned.

2.11 is a standard size, alongside 1.98. Doors and frames are only slightly more expensive than the 1.98 ones.

You have accepted the execution as is. There is no obligation to clarify any matter that might possibly raise questions for the client during the execution. The client may have expert guidance or at least have the contracts / drawings reviewed and explained. I would choose large doors. These are additional costs that you could see every day and be happy about (which is actually quite rare). Doors are usually only replaced after decades, if at all. So the investment in something beautiful is worthwhile.

We had the same "problem" at about the same time. My husband solved it very simply. He screwed thin Heraklith boards underneath and smoothed them on the inside and outside with fine filler. I then wallpapered/painted over it. Problem solved and doors ordered in standard size! I would not want to pay the extra cost, simply because in my opinion the ratio of extra height to extra cost does not fit at all. And the work wasn't that complicated either.

Why actually such a high surcharge? The (standard) higher doors usually only cost 10-20% more than the smaller variant. I would always choose the higher variant. Our architect only plans small doors on request; larger ones would establish themselves as standard.

However, it would not be worth twice the price to me.