This solved the problem on 3 of the 4 machines having the issue. This is after following all of the steps precisely as laid out in the Vmix suggestions on settings to apply in the Nvidia control panel. Recently I ran into a issue with a few of them not showing the 2060 card but discovered that I could tick the advanced box in the performance settings and in the additional settings that show up I could select the Nvidia card there. I am extremely familiar with these machines as I own 9 of them and have all of them running at tip top performance.
I have a Alienware laptop running windows 11, Intel i7 and a 2060 card.