catalina – iMac screen freezes (audio/mic/etc still function but video freezes)

I’ve been having a few odd issues with a new iMac. Screen will freeze occasionally (as will my camera if I’m on a video call) but my microphone, audio, and mouse will still move. If it happens on a video/audio call – others can still hear me and I can still hear them.

I’ve looked through the logs to the best of my ability but cannot see anything that’s going wrong (albeit there’s a lot of logs to dig through). I’ve followed all the normal standard troubleshooting steps but to no avail. There’s no rhyme nor reason/regularity to the freezes either (I’ve ran the system with only a video calling app open and everything else killed and yet it still happens).

I’m at a loss, as is Apple Support, as to what’s causing this or how to even diagnose it as it doesn’t seem to register anywhere.

Specs:

OS: macOS Catalina 10.15.7 (19H524)
iMac (Retina 5K, 27-inch, 2020)
Processor: 3.8 GHz 8-Core Intel Core i7
Memory: 32 GB 2667 MHz DDR4
Graphics: AMD Radeon Pro 5500 XT 8 GB

Additional information: I have 2x Lenovo 27″ screens connected to this iMac