Thanks for the MR. Sadly, this approach to work around the win32 virtual screen clipping (due to mismatch between win32 and Wayland positions) was initially proposed as part of https://gitlab.winehq.org/wine/wine/-/merge_requests/4014, but in the end the decision was to not use it. The reasons for this are discussed in the thread at https://gitlab.winehq.org/wine/wine/-/merge_requests/4014#note_47581 (TL;DR is that doing this would fix some cases but break other cases).
In terms of what would help us move forward, this is also discussed in the earlier MR, in short:
1. Introduce a mechanism for the drivers to tell Wine to not clip some input events. or 2. Some kind of absolute positioning Wayland protocol (ext-zones seems to be the one discussed lately), so we can keep the positions in sync.