This is starting to get a bit chaotic. Previously, the reason why VNC with DRM stack needed was because the content on fbdev was different from the content under DRM, see here: Amlogic VNC on Odroid C5 NO
I can test the CE22 with only one device with an S905X5M, which does not have /dev/fb0 at all. So, I can try to add an fbdev fallback when HDMI is not connected, but I can’t test it without a compatible device.
However, I am open to other ideas…