Having just bought a 75" 4k LG thing last week I can chip in here (and also savvy with rokus, android boxes, kodi, yada yada).
1. the LG has a 150ms sound lag unless using built in speaker - LAG - so adding delay on the amp won't fix it. across all content. how the flying fuck that got through QA I have no idea... so basically using the TV for anything other than a monitor is a waste of time... luckily thats my main use case..
2. I use it via a mac mini - and kodi. kodi lets me view H264 4k content fine, but the mac mini hasn't the oomph for H265 4k... and of course netflix, amazon won't display higher than 1080p via safari, and even then you won't get HDR or DD5.1 which is kinda shitty.
The LG does play H265 stuff, VP9, etc. It plays 4k netflix HDR, etc, etc - all good except for the 150ms sound lag which makes it all for nothing unless you want to switch you watch it all with the shite sound out the built in speakers.... its the sort of thing you wish you could bash some engineers heads together at LG over.
So - alternatives for H265 4k or netflix 4k+DD ? well, a cheap 30 quid android box would do the H265 4k and DD ok - but the problem is that only a few 'authorised' devices are allowed to access netflix 4k streams - apple tv, LG and other big tv companies, and roku, etc.
None of the chinese android boxes are allowed - so your limited to 1080p max streams on them.
what a pain in the arse. why something has to be as complicated I don't know. It's like they want people to pirate stuff.