I broke my spreadsheet dropdowns

Somehow, the dropdowns (data validation list) stopped working within my entire workbook. It is the "Weekly Schedule Planner" template that Excel offers. I added 2 additional picks to the list. Then I updated the conditional formatting to assign them specific colors. Somewhere in this process or perhaps accessing this shared file through M365 Copilot on my phone, the dropdown arrow on the cells is gone! The options are still there when using the formula box at the top, albeit only when I backspace first. 

I have tried everything I can think of to get the dropdown arrow to show, and it doesn't. The first column in the To do items as well as each day is set up with the list. I used Ctrl-G to make sure there wasn't an extra cell hiding somewhere, too. 

We will probably start fresh with a new file in 2026, so it's not the end of the world if I have to struggle through the next six weeks, but it might be. 

TIA for any advice that might fix this.