I would keep the LG. They make nice TVs. I have not done a comparison, but not sure a Hisense would be a step up.
A Shield Pro would definitely work.
As @JaysPlex mentions, a less expensive option would be an Amazon FireStick 4K or 3rd Gen Cube. Amazon devices run Android, like the Shield. They will play subtitles without causing video transcoding.
The differences between the Shield and Amazon devices is in audio support (and all the Amazon stuff on the FireStick home page).
With the FireStick 4K, TrueHD audio will be transcoded by Plex Media Server. DTS audio formats will be decoded by the FireTV Stick and delivered as Dolby Digital or Dolby Digital Plus.
The Cube v3 will passthrough TrueHD audio. With DTS audio formats, only the lossy DTS 5.1 core is passed.
So…
If you’ve a sound system that supports lossless audio such as TrueHD + Atmos and dts-HD MA, go with the Shield.
If you do not, take a look at the Amazon devices. You’ll get playback w/o video transcoding and you’ll save a bit of coin as well.
