Formula that returns the column reference of the last non-zero value cell in Sheets

Question

I have a list of values by month for multiple users in a Google Sheet (trailing 12 months). In another column, I need to provide the column reference for the last non-zero value in that row. So, for instance, if all 12 months are non-zero, the formula returns 12, but if the last three months are zero, the formula would return 9.

This question returns the last non-zero value (so close!) - I am looking for the column reference for that value.