Photovoltaics initially without storage

That is at best 16 modules, if the dimensions roughly fit. Standard modules are 160x100cm.

32x300 = 9.6kWp

The rest should be planned by a professional, as I can hardly help you with that. An individual assessment is more beneficial than guessing here.

I am already working on it, have contacted 2 solar installers...

In which region are you? Unfortunately, I can't see it in TT.

We will soon be building in Thüringen.

Since it is not in our region, I recommend a forum for this specific topic, which is visually very blue with some yellow and can definitely be quickly found by Google search as photovoltaik Forum com. The real experts and enthusiasts on this topic gather there. There are also surely providers active in your area.

I have already discovered that too. From there, I also found a bidding platform; until yesterday, I had already spoken to 2 solar installers and another photovoltaic company on the phone. Let's see what they offer...