Use a Shield Pro 2019. Upgrading your PC will not work.
Plex Media Player on a Mac/PC does not pass HDR to the TV.
Reference: this post.
Yes, since your receiver supports TrueHD and dts-HD MA.
Details:
If the audio is direct playing or direct streaming, then the Shield will play PGS, VOBSUB, and SRT subtitles directly, without forcing a video transcode.
If the audio is transcoding, and you enable subtitles of any type, it forces a video transcode by the Plex Media Server. Plex does this to keep the video, audio, and subtitles in sync.
ASS subtitles: ASS subtitles are text based, and may contain position, font, size, color, etc information. To the best of my knowledge, the Plex client on the Shield treats ASS subtitles the same as PGS and VOBSUB subtitles. Translation: I’m 90% sure that is true based on other threads I’ve read. However, I’ve no ASS subtitles in my own libraries, so cannot personally verify.
