Onkyo TX-NR3009 vs Onkyo TX-RZ810 - how important is 4k passthrough and HDR10?

Looking at a used Onkyo TX-NR3009.
I like the pre outs and bi amping capability, and plenty of power reserves (I am potentially running some critical (low impediance in the woofer) speakers.

But not sure how well it works with my Vizio M75 4k.

It says the Onkyo does NOT have HDR10 or HDR10+, and NO 4k PASSTHROUGH. Not sure how that would effect my picture quality.
Does not even have Bluetooth. Alexa would be nice

ALTERNATIVE I am also looking at (used), the (assumed) slightly newer:
Onkyo TX-RZ810
Has HDR10 and I think 4k passthrough
Also decent power for 2 channel audio and bi amping capabile, plenty of pre outs.

When does the lack of HDR10 and/or HDR10+ become an issue? I am guessing: When TV receives video signal from cable box, receiver is not 'involved' (but needs to be able to pass 4k signal through to TV, right?). But when using another source (BlueRay DVD, Roku stick, etc)?

Both seem to be competent to drive more difficult loads in 2 channel audio. 

Both can be used 'out of the box' for bi amping, and have plenty of pre outs to use external amps. None have a 'pre-main' bridge or pre-out/main-in splitter (to use all those unused main amps for other uses). 

Comments? Suggestions?




I own the RRZ630 and the 4K features are excellent. I would not get a receiver without them. The amps work great, I think you will like the sound. 

Under what scenario do I need to use the '4k passthrough' and HDR of the receiver? 

Is that already needed when 'passing' the cable box HDMI signal to the TV (via receiver)? Or only if a source outside the cable box or TV (think Roku app) is used, like a Blueray player?

Ditto with HDR.