AV1 Playback hangs on Sony Google TV / Android TV

Server Version#: 4.156.0
Player Version#: 10.30.6.4151 (f1455a3f)
On a Sony X93L, attempting to play a 4k HDR AV1 file gives me an endless loading spinner (no percentages, just the circle spinning). I can play 4k HDR HEVC / H.264/5 no problem - AV1 will not work. I can play the same file just fine on Kodi app on the same TV. TV lists AV1 codec support. Plex server logs suggest direct play is being initiated, file handed off to the TV, but no playback happens. I’m thinking the client player is simply incapable. I’d love this to be fixed. I’m open to suggestions, already messed with the Android profile significantly with no success.