I might just be super dumb, sorry. I've watch numerous videos and read other post, but I'm missing something about this. I've basically spent half a day just trying to figure this out.

As the host, I add an Audio Input & use the checkbox [X]option to 'Mute in headphones' but the guest caller can't hear me. If I use the gear icon on that Audio Input and click the headphone icon to green, then I start hearing myself my headphones... but then the guest can hear me too.

I just can't figure out a way to be host and hear the guest, but not hear myself in my own headphones.

That solved it, thank you!

I see now where I went wrong. The default Audio Source for me when adding a Video Call, was 'Headphones' & switching that to 'Master' fixed it... in combination with creating a Audio Input using the 'Mute headphones' option.

Thanks for info on right clicking the callers in order to change the Audio Source, it would have been a bummer to have to create them from scratch.