I usually set up things way differently between Excel stuff for myself and Excel stuff that anyone else is supposed to touch.

Just colour all the untouchable cells dark grey or black bg on black text, or put on a separate sheet entirely.

I used to teach Excel at an adult vocational college. When I moved into the corporate world, I quickly learned why the University of Hawaii's research found that well over half of spreadsheets have critical errors. Even the people treated as Excel experts were often clueless.

I'm not saying that spreadsheets should be banned from the workplace, but they definitely need to be very tightly controlled.

Oh, and always, always lock formula cells, even in sheets that never leave your control. :) If possible, make use of Excel's native data forms, too.

I have a process that use python to read some excel files from the commercial team and then the result feed a dashboard. Every week the assistant of the director write me saying that the dashboard didn't update correctly, I look what happens and everytime it was the commercial people messing with the excel where it was already told hundred of times they should not mess with anything except their corresponding cells. Next week I'm learning how to block the file except the cells they should edit.