Which embedded systems actually run GLES on Linux stably enough to do anything with Wayland? My experience is the choices are:

Use a binary blob that only works with a 3 year old vendor kernel, and works most of the time (but you can't fix it when it doesn't work, and if you are compositing most of the time isn't good enough)

Use a mainline Linux kernel that is so buggy that fixing the bugs in it is a full time job

Use fbdev