Not sure about you, but as I wait for that person to connect on zoom, I use those 30 seconds to send a msg or browse my twitter feed or finish that email. Basically I cram into my (rather long) working day as many tasks as possible.
It is likely that you are observing quite a few more opportunities to also make your team more effective, to fill those slack times with one or two more tasks, to increase the productivity of everyone to make you able to make as much as possible happen.
Don’t do that !
And there are two reasons why you should instead give value more that magic slack time,
one is important, the second one is fundamental The more your work, the less productive you are
1. The graph below is just one of many visible expressions of what we all know:
that pushing you and your team too much actually creates a lower rate of productivity.

2. Even more important to create truly innovative teams is to give them space to do nothing.
When you have time to think, to allow information and inputs to connect, that is when the truly good ideas arise.
Some of the best innovators, when they are stuck, stop. They close all their tech, go for a walk, sleep it over.
But it’s urgent! Even more reason to stop because urgent deadlines never stop, in fact the more productive you aim to be the higher the number of urgent deadlines will appear in your agenda.
Don’t be busy, don’t “be urgent” instead enjoy and let your team enjoy that slack time where the best innovation happens.