The problem with TV based apps is a hardware limitation on the LG TV. Look at the block diagram in the thread I linked in my first post (this one). It shows the internal connection as ARC, not eARC. You can follow the conversation over to the AVS Forum for additional details.
External HDMI connections follow a different path (refer to diagram). Note the eARC arrow into the box labeled MUX. This is how external devices can pass TrueHD/dts-HD/etc audio via HDMI-eARC (if I’m interpreting things correctly…).
You could also connect any devices directly to your AVR instead of the TV. This takes the TV out of the picture as far as audio passthrough, codec support, etc.
Regarding the Shield as a client:
Purchase the 2019 Shield Pro. It supports Dolby Vision, which is not supported by the pre-2019 models.
Do not purchase the 2019 non-Pro “tube” model. It has stability issues. Query the forum for “Shield tube” to see the reports.
The 2019 Shield has other features such as “AI Upscaling,” which apparently helps quite a bit with lower resolution media. You can read product reviews online and forum posts for additional details (I’ve a 2015 model, so no direct experience with the 2019 enhancements).
Regarding the Shield as a server:
It can work well, but does have its limits. The documentation has helpful information. You will have to keep your media on external or network drives. You will have to move your Plex server folder (metadata) to an external drive, especially if you use chapter thumbnails, etc.
If you are only streaming within your local network and with minimal transcoding, the Shield will work fine (especially since the Plex client on the Shield direct plays almost everything).
You can use the Shield as a Plex client then enable the Plex Server later if desired. Plex has no limits on the number of servers on an account (or it is pretty high if it exists), so no problem running Plex Server on both your PC and the Shield.
I have a 2015 Shield Pro, w/ 500 GB internal drive. I do not use it as a Plex server. The last time I experimented with doing so, it was noticeably slower than Plex on my Synology DS918+. It transcoded two, simultaneous lower bit rate 1080p streams OK. I did not try transcoding Blu-ray rips, 4K media, etc.
The slowness was noticeable in how long the Shield took to scan libraries, generate thumbnails, etc. My Shield took several days to generate thumbnails for a ~800 movie library. The Synology did this in about 2 days max. Part of this is due to the 2015 Shield having a horribly slow, encrypted hard drive. A unit with USB3 drives/SSDs should be much faster.
Hope I answered your questions. Let me know if I missed something.
