Yearly calendar/scheduling

Hi all,

I'm working closely with EA's in a large company to try and help them catch up on large projects they've had for a while. One of them is a system for their annual scheduling for meetings and regular business cadence. We're looking for a way for EA's in different departments to be in charge of their own calendar but also have a master view calendar for certain employees in the company such as the execs to view and know what's happening in different departments or other regional offices. The going theory right now is use Smartsheet to track meetings and whether or not they've been scheduled, who's in charge of scheduling, etc, and then export to excel to use with a Power BI dashboard for viewing. I can't help feeling like this is way too many steps. I'm wondering what everyone does to track three million meetings and recognize when they need to be scheduled, by whom, etc. What do you do? Any suggestions? Has anyone tried something and found it didn't work for them? Why?

Thanks all.