But on that day all of those people might've chosen to work from home so you sit all alone in the office.
The hybrid solution only really works well if the office days are the same for everyone.
If the staff actually find this face-to-face time valuable, they'll organize and go into the office themselves, personally I've had zero requests from anyone to do that outside of explicit team-building activities.
My enthusiasm for RTO is not about changing the venue from which we take our Zoom calls, but about changing our relationship with Zoom to something like its pre-pandemic state. To have some conversations naturally again. But there's no getting around that the WFHers would have to either show up or be excluded from them.
I personally find Zoom excruciating, and I blame the transition to remote meetings for all communication for turning a once optimistic and joyful career experience into a miserable slog.
We used to have so that every Thursday was "come to the office if you can" -day, but switched to the poll system.