The trick to get around this is to move smoothly up and down the gradient of social interaction intensity, never dropping below a basic floor of presence: the sense that there are other people in the same place as you.
Instead of having two modes, “in a call” and “on my own,” we need to think about multiple ways of being together which, minimally, could be:
In a video call
In an anteroom to a video call, hearing the sound of others
In a doc together
On my desktop but with the sense that colleagues are around
And the job of the designer is to ensure that their software ensures the existence of these different contexts, instead of having the binary on-a-call/not-on-a-call, and to design the transitions between them.
In this sense, trust is a polarizing strategy, and it's one that is important to apply early on in the relationship before someone becomes important to you. If you trust someone excessively and it goes badly, but they don't matter to you, you can just kick them to the curb. In general, trusting someone at a level that seems slightly excessive for their level of importance to you will help you sort people in your life who you want to be more important to you than they are from those who you want to be less important than they are.
And it does need to be excessive. It needs to be trust beyond reason. Not beyond all reason, but somewhat beyond what currently seems reasonable. If it is not, then unless they are prepared to take the first move, you will never find the signs you need to move to a higher level of mutual trust.
Sometimes this will go badly, but you need to be able to try bad things.