I am confused due to the fact that I keep getting no result when trying to find the 1st empty row. It works fine with some other spreadsheet, but it doesn’t with a new ones. I created a test scenario with a brand new sheet in order to present the problem.
You won’t get an empty row in the API when looking for a blank column if all columns are blank because the Google Sheets API does not treat fully empty rows as part of the data range, thus ignoring them in queries.
However we can work around this.
By:
search by your key row where this row exists. For my example A is my key row.
Make sure to sort order by descending
Order by row number
Now we will receive the last row number with a value in it