VDPAU has been deprecated for quite a while now, Nvidia's moved to the CUDA based nvdev/nvenc API.
As kodi doesn't support nvdec the nvidia-vaapi-driver is now used - kodi uses vaapi and the nvidia-vaapi-driver "translates" that to nvdec.
Nvidia RTX50XX (plus future models) aren't supported in LE as they would require a different kernel driver (which only supports very recent nvidia cards so we can't just switch to that as it would drop support for a lot of older cards).
Trying to support nvidia cards has been a huge PITA in the last year (even more painful than before) and is bloating our images a lot (all the proprietary nvidia libraries and firmwares are huge) so I wouldn't be surprised if we end nvidia support sooner than later.
so long,
Hias
