Transitioning to Opt-In Office Reopening

Hi MS Community!

My organization recently adopted Microsoft Teams across thousands of employees; we're also in the middle of a transition from mandatory work-from-home to opt-in office reopening.

I'd like to set up a system for the ~400 employees at my local office to organize and communicate when they will choose to commute to the office. My vision is that each employee can somehow record the days they plan to be in the office (for instance, creating an all-day event on my personal calendar on the dates I plan to go in), and it is automatically loaded in to a list/calendar/pivot table that shows who is planning on coming in each day.

The execution is entirely flexible - I just want a simple answer to questions like "I wonder when Jonny is planning on coming in this week?" or "Who's going in to the office tomorrow?" This could be segmented by team, leverage an app, or just be based in the calendar. I just want to improve connectivity and make it easy for people to participate in the system. I thought about a shared calendar, but I haven't seen an easy way to view something like that where there are instances for numerous people. I've also thought about some kind of power automation flow that would populate a calendar-like table based future calendar events, but that ran into permissions/sharing issues.

I'd love to hear any advice on the above or current strategies folks are employing - thanks for the help!