There are two hanging patches to KWin/KWayland (D1230/D1231) that add support for remote access via passing GBM file descriptor with Wayland messages.
Unfortunately they are not compatible with most remote access implementations.
To address this the PipeWire glue layer should be created.
This task tracks progress in implementing such protocol from the ground up. All questions/clarifications regarding PipeWire support also go here.