That is incorrect. See Plex on Vega OS devices (Amazon Fire TV Stick 4K Select). However, it does have the new experience user interface.
As mentioned, the Plex Android TV app has not been updated to the new experience app. This includes Amazon devices that still run Android TV (AFAIK everything but the FireStick 4K Select). However, it is Plex’s intention to move all apps to the new experience UI. Plex has not provided a timeline as to when that will happen.
Another option is using Kodi with the PlexMod for Kodi plugin.
Many people are using an Ugoos 6B+ and loading CoreELEC + Kodi + PM4K. The combination supports passthrough for lossless audio (TrueHD Atmos, DTS-HD, etc.) and Dolby Vision/HDR10.
