I finally got my mancave finished and I'm ready to enjoy 4K HDR content and I'm running into some glitches.

I'll list 'em all and if anyone has suggestions on any of them, I'm all ears.

a) Opening scene in UNFORGIVEN 4K blu-ray - the highlights in the sky have bad artifacting. It's not subtle. (image below is to show scene in question, not my screen nor showing problem)


b) intermittently get HDCP error when trying to watch 4K content on Roku.


c) got same "purple HDCP error message" while playing back Beatles "LOVE" DVD-A (audio continued fine, but OSD went out.
d)sometimes rather than purple error, screen will either start sparkling white dots and then go to complete snow.


Power cycling and/or pulling and re-seating cables seems to always resolve it, but that's not really a solution.

Thoughts?

chain:

roku->marantz sr5011->lg C7 oled
oppo udp-203->marantz->lg

HDMI cables to/from roku and oppo to Marantz are Rocketfish 6' 4K UHD/HDR cables from bestbuy.

in-wall HDMI cable from Marantz to LG

Ideas?