Spoke with our electrician. Unfortunately, back then he only installed a 5x2.5mm2 cable into the garage... :-(
So a maximum of an 11 KW wallbox is possible. However, this also does not need to be registered with the energy provider.
He had asked me back then what kind of cable he should install... "Yeah, just do one for a wallbox and that's it," were my words! Damn!
Pulling another cable, or a thicker cable, is too much effort for me... For that, I would have to lift dozens of meters of pavement, etc. No desire!
So he should just simply install an 11 KW wallbox in the garage and that's it!
It would be great if it was a box with WLAN... But for 900€, you should be able to get something decent, right? The labor cost can't be much if the cables are already running from the fuse box (not connected!) to the destination...