Because 4K is still in change mode, it is difficult to figure out what exactly to buy these days. Yeah we know what they are saying right now, but they've said many other things as we've transitioned to 4K.
Which means whatever you buy today may or may not support whatever becomes the 'final' specifications, and while 'they' keep changing things, it is affecting our wallets as we try to keep up.
For me I've decided that I'll stop right here for awhile. I have a perfectly good 2015 4K Sharp TV that doesn't support HDR and probably won't. But since the vast majority of actual 4K content is via streaming it isn't a huge issue for me as I have no intention of ever getting a 4K BluRay player.
The prime benefit these days for the 4K TVs is up scaling 720/1080 content that is the vast majority of content out there.
Unless you just want to spend money to get that 4K tv and buy a new AVR you could do what I've done. Attach my 4K content box directly to the TV and use optical to get the audio. Since all the streaming and sat provided 4K is only providing DD anyway, it works just fine. Just makes diddling with remotes a little more, uh, 'challenging'!!
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