How can I avoid Dolby Vision transcoding in webOS?

[el_Pedr0]

I want to play Dolby Vision 5 and 8 mkv files on my webOS LG TV without transcoding. However I have tried a number of Dolby Vision files and all end up transcoding, which my non hardware accellerated hardware can't handle. 

I have read that it should be possible (JellyfinForum GitHub Reddit). I have failed to find a comprehensive guide and some of the information I've come across talks about GUI configuration options which I don't see, so might relate to a version or environment that does not match mine.

Example video: 4K HEVC Dolby Vision Profile 8.1 (HDR10)
ffmpeg log: https://pastebin.com/jCLcrpSk
Jellyfin log snippet: https://pastebin.com/S36kyhCX

Any advice on how I can get DV files to play without transcoding would be welcome.

Environment:
Client: LG OLED55B7V WebOS 06.10.65 (rooted)
Jellyfin server: 10.10.7
OS: Ubuntu 24.04.3 LTS (in LXC running on Proxmox)
Jellyfin webOS client: 1.2.2 (via LG content store)
FFMPEG: /usr/lib/jellyfin-ffmpeg/ffmpeg -version -> ffmpeg version 7.1.1-Jellyfin Copyright © 2000-2025 the FFmpeg developers

NB: In my browser, clicking on the links below yields an error message, but right clicking and open in new tab works.
Transcode Settings on the server: https://pasteboard.co/CoNHKQUwTvmY.png
webos client settings:
Jellyfin webos playback Audio
Jellyfin webos playback Video
Jellyfin webos playback Music
Jellyfin webos playback Advanced 1
Jellyfin webos playback Advanced 2
Jellyfin webos playback Advanced 3
Jellyfin webos playback Video Advanced
Jellyfin webos playback Audio Advanced