Basement wall height, too low?

yes, with us the roof pitch is above that as well.
We really didn’t pay attention to it. Doesn’t matter now: the window has blinds and is closed facing the street when we stay there

it’s the same with us. The general contractor had even planned it lower. I then raised it as high as possible.

Raising the roof is the alternative. But the general contractor wants to save the costs for it and also keep the planning mistake from us, so this route was chosen. When we finally noticed, they presented us with a €4800 surcharge for raising the wall by 20cm.

We noticed and addressed it during the planning. After that, we set the windows as high as possible. We have a knee wall height of 186.5cm. Roof pitch 26°. Roller shutters are not possible. We never thought of raising the roof – the general contractor didn’t mention this option either! On the ground floor we adjusted the height, and we were basically satisfied with the height in the attic and then lost sight of it.
We just accept that the parapet height is a bit lower...

If I win the lottery, I’ll raise the roof by 1.5m – otherwise it stays as it is (it will only really show once it’s built)...

The alternative would have been no window at all in this spot? Then I'd rather take this compromise and maybe even a foil as a privacy screen

No, it could have been moved. Then it would be at the corner mirror at the same height as this one. That would have even looked very good

But I want to say something completely different here. Also, this is not about our window, but about the basement height of the OP :

I have erased the word would have from my mental vocabulary! Why and how life is different without it? Much better, because I don’t compare the current state with something that doesn’t exist (or wasn’t supposed to exist back then either)
Why should I wear myself down thinking "if only I had bought those stocks", "if only I had been faster back then", "if only I had studied back then" or "if only I had paid attention, then..."
I have a really great house, and I’m happy to live in it. It may be that something annoys me at first or from time to time. But it doesn’t change my life if the window were different now. It’s about things that I or we messed up. But why should I complain to myself? Be dissatisfied because I "failed" at that point?
NO! I don’t do that. I have achieved a lot and good things and I’m still going!

And just as the window is now as it is, the basement here is as it is. Live with it! And live well with it! Make your fitness oasis: everything works at 2 meters height too. The Pax doesn’t fit. Or does it? Doesn’t matter, then take the Billy.

You have the choice here and now to either be annoyed forever or to bury the topic.

If I win the lottery, I’ll raise the roof by 1.5m – otherwise it is as it is (it will show itself once it’s built)...

If I win the lottery, we’ll rent an apartment in Spain, Italy or on Rhodes – as a second home... the window stays where it is :P