The current TigerVNC add-on appears to be compiled against X11 libs so I doubt it runs under Generic, and it probably runs into the same zero-copy video pipeline issues that all the Ambilight setups (that depend on copying buffers that can no longer be copied) enounter under GBM/V4L2. If my guess is correct the add-on will need to be dropped when we remove X11.
Interestingly I'm running two Intel NUC boxes both manufactured in the same year!
and Tiger VNC would only work on one even with both installed with;
LibreELEC-Generic-legacy.x86_64-13.0-nightly-20260519-a7d93f5
I'm not very good with GPUs but I figured out one box had GPU
GPU: Mesa Inte(R) HD Graphics 500 (APL 2)
which VNC would NOT work on
But the other had GPU
GPU: Mesa Inte(R) Iris(R) Graphics 540 (APL GT3)
which is is far superior and VNC works! sorry, useless info but it does save me from walking all the way to the living room to setup Kodi for evenings entertainment... thanks!