the problem with this kind of setup is AVR always decides the lowest quality of both outputs. since OUT2 will say it can't handle HDR and/or cant do HDCP handshake, Netflix and other 4K HDR sources will output SDR and even sometimes 1080p signal. that means your shiny 4K HDR tv is worthless :(.
Solution (i am still working on this):
option1: put a HDfury DrHDMI right after out2 of AVR. you can set a profile in this device and the Sources will see 4K HDR and no HDCP problem. after DrHDMI you have HDR signal, which needs to be converted to SDR...for this you can use HDfury X4.
option2: HDFury DIVA....this device takes a HDMI source (actually it has 4 HDMI input), and spits 3 signal...4K HDR (goes to TV), 1080p SDR (goes to RPi), 1080p with full audio (can be hooked to a AVR, but you can ignore if you use this after AVR)
unfortunately whole setup cost a lot 