comments:
Its really easy, you dont even need a handyman or DIY. They literally sell the solution https://www.amazon.com/Portable-Universal-Casement-Conditioner-Waterproof/dp/B0C5Y2ZLR8?th=1 But people are too lazy to want to solve the problem apparently.
our windows do not allow for window units Yes, they do, you just need an adapter for it. For example https://www.amazon.com/Portable-Universal-Casement-Conditioner-Waterproof/dp/B0C5Y2ZLR8 Its really easy to solve problems when you actually want to solve them.
Germany is the most expensive country in the EU for air conditioning install, unfortunately. Get a dual hose portable unit, and a window attachment kit. Even euro windows can be made to work. This is a hardcore semi-permanent version. https://martinsonmanufacturing.com/products/portable-ac-casement-window-vent?variant=44971153621200 Something like this is cheaper and flimsier but still works. https://www.amazon.com/Portable-Universal-Casement-Conditioner-Waterproof/dp/B0C5Y2ZLR8 SF generally doesnt have standard American windows either, people have to make do.
What about https://a.co/d/09r2iZDD ?
Those don't work for casenent windows like what OP described having, unfortunately. The kit I was thinking of is a soft fabric that seals around the edges of the window and does not require removing the screen, like this: https://www.amazon.com/Portable-Universal-Casement-Conditioner-Waterproof/dp/B0C5Y2ZLR8