While I try to get it fixed somehow (only way I see at the moment is an repair cafe) I work with 2 display I scavenged.
Nothing easier than that I thought, simply buy a USB-C dock with two HDMI ports. Boy was I wrong.
It works fine on Linux.
On Windows both display use the same resolution which leads to a distorted image on the higher resolution display.
On #MacOS both external screens show the same image. This is said to be a limit of MacOS but I have a hard time believing this. I can add a second USB-C to HDMI Adapter and both external displays just work fine. Additionally it should be possible daisy chain thunderbolt displays. So it feels rather like an artificial technical issue. E.g. the vendor would need to use different more expensive chip (or really use Thunderbolt).
Can anyone #Recommenced a Dock which supports two or more display on MacOS?