Open Plex Media Player
put it into the ‘TV mode’
click on your user avatar
Settings - Audio
Device Type = HDMI
Channels = 7.1
Device=pick your HMDI audio adapter
After you switched the Type to HDMI, there will be additional check boxes underneath with the various surround formats listed.
Tick all those which your AVR can decode on its own.
You can switch back to ‘desktop mode’ if you prefer it, but I don’t recommend it if you want to use ‘Allow Display Mode Switching’ as well (to adapt the refresh rate of your tv to that of the media file and thus get a judder-free video).
