Zoom recording video quality challenge

I am using an ATEM Mini Pro with USB C connection to a MacBook Pro. A second computer (Windows, Mac, whatever) is hooked up to the ATEM Mini Pro via HDMI. During a Zoom call the video quality of the second computer is fine during the call. However, in the Zoom recording the video quality of the second compute is poor. In the same recording the video quality of a screen share of the MacBook Pro is very good. Any insights on why the Zoom recording of the second computer is so poor and how to resolve? I have tried switching to various HDMI cables and enabled high def recording. Tried both 30 and 60 fps. TIA.