How do I return the minimum date based on a measure value

I was wondering how to return the minimum date based on a measure value

I have the table here where created_at is a column in another table 'BudgetViewSnapshot' and subunboughtcount is a measure in a table 'NewSSDetail'

The desired return result would be the minimum date that the subunboughtcount turns to 0. So in this table it would be 12/6/21.

Thanks,