Asking to see what is the art of the possible here.

We currently use an event tracker in an excel sheet. This is just a hand-made calendar for the year (days are rows) and the event location down the side.
For specific dates, we type in a cell, the company name, how many people are attending and some misc info. This is then made into a merged cell and coloured specific to the company.
This works great and allows us to print off a year (monthly calendars wouldn't work for us).

The issue comes when we try to extract data from it. If I want to know how many people from company X attended various events over a period, I can't. I have to manually look at each cell for that company and write down the number of people we have on record attending.

I did see this leave tracker which gave me hope.

End game - There would be a tab where I could enter the raw data. Company name, how many people, start date and end date etc.
Then it could take this information and populate another tab which contains the calendar. Putting that company in the right place with the right colour and shows briefly how many people are attending. Any changes made to the details tab would reflect in the calendar.

This way I still get the printable look of a calendar but have the details tab so I can extract data. Best of both worlds.
Unable to produce a dummy or you look at right now, but if required I can try to make something. Just hoping for some initial thoughts.

All help is very much appreciated here.