@afrantzis I think you should either try to find way to translate Wayland coordinate space to Wine coordinate space, maybe not worrying about where the windows actually are in Wayland space.
Also, unless this MR is a hard requirement for the rest of the driver, I think you can perhaps try opening merge requests for other more independent parts of the driver, in order for it not to be blocked until we have a better solution here. I believe we would be very happy to have even a roughly usable driver for 9.0 (in two month time, if that's reasonable for you ofc).