I can’t use this formula to get results like in Excel.
Where did I go wrong?

I want to find a working day that cuts off Saturday and Sunday. by starting on 2021-11-01 and set the date to work is 5 days
Thank you very much for helping me.

=2021-11-01 is not understood as a date, I’m guessing—I think it’s understood as an arithmetic expression that evaluates to 2009.
Try changing A1 to =DATE(2021,11,01).
What are you trying to get for a result? Maybe there is a better way instead of trying to use excel formulas.