Use a custom formula to update cell color when a scheduled time is past. For example:
=IF(NOW()>C3, "Expired", "Active")
This method shows expected outcomes.
I have tackled a similar challenge by leveraging Google Sheets’ conditional formatting rules. Instead of returning a text value, I formatted the cells directly to highlight when a scheduled time has passed by using a formula rule that compares the cell with NOW(). This method made it easier to immediately see the expired entries without cluttering the sheet with extra columns. From my experience, this approach is not only cleaner but also performance-efficient for larger datasets where running many formula recalculations can slow the sheet down.