RTX 2080 ti - will only duplicate to HDMI tv

My main monitor works fine, via display port. When I try to add display to my tv to watch things on there, it will only duplicate. Everything else has a blank screen.

My main monitor (DP) is running at 1080p, 165hz. The tv (HDMI) is a 4k tv, 60hz.

I've reinstalled the latest Nvidia driver, and I'm not sure what else to do.

ETA: Windows 10, upgraded from a RTX 2080 (Emergency upgrade, not just a "I'm done with this good card deal), worked fine with the 2080.

Also, I used multiple HDMI cables. First I was running into an HDMI matrix with cable 1, then I plugged straight from the card to the tv with cable 2.