South terrace: Glass roof with upper or lower awning?

No, I think it's mathematically great, but I have no use for it and don't drive super expensive cars. Sometimes ideas like this help to find solutions outside the box, hence the impulse.

And then a question in the other direction - what is the cheapest solution? They have about the same dimensions. Where can you find good suppliers?

Polycarbonate sheets.

We decided on the under-roof awning. If I imagine everything that would have ended up on the awning during the summer on the terrace roof, then good night. For heat protection reasons for the house and also for the terrace slabs, we had the awning extended almost constantly throughout the summer. I don't care if it might rain early or there's some wind. It might look a bit different with fixed sides. With sliding elements, I can't really estimate whether they are left open all summer anyway. (Winter garden aside)