Smart TV apps and IPTV-based Live TV

Server Version#: 1.43.0.10492 (official docker image)
Player Version#: it varies.

I have IPTV-based Live TV/DVR in Plex (via Threadfin) with Plex providing the EPG. This works great for me as I was previously using a HDHomerun Prime and it is still the backup tuner (at least until they kill off QAM/CableCARD). So, I manually mapped the available channels to the Fios channels and nothing changed as far as the lineup. Anything to avoid renting boxes from Verizon.

Live TV will play fine via app.plex.tv, iOS/macOS apps, and Apple TV. Apple TV can even direct stream it, no transcoding load at all. However, I have so far run into issues on multiple smart TV platforms when trying to watch some or all channels. This was not the case when I was transcoding MPEG-2 from the CableCARD, but it seems to be the case when it comes to IPTV because who knows how the source is encoded, and even transcoding doesn’t seem to fully clean it up. It seems the client has to be very tolerant of different profiles, and that is mostly up to the underlying smart TV OS.

Here is what I’ve found:

Google TV/Android TV/Fire TV (also based on Android): no channels play, or play briefly and then encounter a playback error. This is the case with direct stream or transcoding. Does the Android app do this in general?

Roku: some channels play, some retry a few times and then give playback error. Direct stream can be set to none, allow, or force… doesn’t matter. And what’s with the UI on there? It’s not like any other platform’s Plex app, you can’t even reorder stuff!

Samsung (Tizen OS): This just works. Frankly I’m impressed. The UI is kind of laggy on my old 2020 model but everything plays perfectly, even when “force direct play” is on to make live tv direct stream.

Vizio (smartcast) and LG (WebOS): Don’t have these. I do know Vizio was ok before I switched to IPTV. Does anyone know how well they work with it? As I understand it both of these are basically web app based platforms, but it will rely heavily on the codecs the TV supports as transcoding does not appear to really fix all IPTV stream weirdness.