Hi,
I just use OpenATV all the time, don't really use HD channels and therefore have not noticed any problems. Been a while since it was released and would have thought there would be an update for it by now.
Sometimes I eject the SD card out and boot in to WeOS so as I can use Kodi, tried it with the family over the weekend and they just don't like it compared to E2. Waiting for the box to start from standby when you want to watch TV seems to take ages, but once up and running is OK, but with no epg like you say which is shit. Even caused a few swear words on Friday as one of my sons somehow got it in to Radio mode, and ended up having to search through the forums to find how to get back to TV.
I have tried TvHeadend, but seems like too much effort to get it perfect, and don't really fancy using Kodi interface for TV. Afraid I can't help you with that.
On another note the WP1 is brilliant, using PB Enigma image, and it has native Kodi 17 in the menu and never misses a beat. Can't believe how backwards the software available for the WP2 is compared to WP1.
Have you tried the Android TV rom, again you need to be able to use TvHeadend though?