*nix noob here. I moved a Plex server from Windows and everything is working flawlessly except HDR. The client side should be good (NVIDIA Shield and LG OLED TV that both rendered HDR fine under Windows) and I know my server hardware (10th gen i7 NUC) is capable so I’m assuming I’m just missing some packages and/or config. This is a fully-updated EndeavourOS installation but I think I remember having the same issue under raw Arch.