The Video Out option won't show up for your AV inputs, only the built in apps.
However, I found it strange an AVR as powerful/full featured as the 3060 couldn't do what you wanted so I did some digging in the manual and settings and sure enough, there is a way.
First, you need to go to the setup menu > function > input assignment.
Assign the optical/coaxial input you want to use (in your case whatever one your PC is on) to the AV input that the video source you'd like to view while your PC audio is playing is hooked up to.
Eg: for my test, I ran optical into optical 1, then assigned it to AV 1 which my Oppo is hooked up to.
Next, you'll select the video source you want to view with your PC music.
In my test, this was the Oppo.
Finally, you will now bring up the option menu on screen and under 'audio select' you will be able to select the optical/coaxial input from your PC that you assigned to the source.
I was able to watch video from my Oppo and listen to music from the PS3 no problem.
Now unfortunately, with this way if there are potentially multiple video sources you want to use with the PC audio input, you'd have to change the input assignment each time. I thought about registering a scene to save the settings but the scenes cannot include input assignments as part of their saved parameters (annoyingly).
However, this will let you ditch your other device, and at the end of the day even switching input assignments is super fast on screen.
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