The hardware decoder is reporting missing information in the media; which normally indicates a media problem and not a decoder problem. FWIW, i'm running my own RPi5 development image (LE13 not LE12) with a broadly similar setup and I don't see the same errors with a wide selection of test, broadcast, and self-ripped 10-bit HEVC media.
Feel free to test https://chewitt.libreelec.tv/testing/LibreE…-12.90.1.img.gz - make a backup of /storage/.kodi first as Kodi does not support downgrades. There are also some binary add-ons missing in the repo that image uses right now, but that will resolve itself over the next 24h or so as they are built and published.