A family of Microsoft spreadsheet software with tools for analyzing, charting, and communicating data.
You can use
=WORKDAY.INTL(DATE(2025, 8, 0), 4, "1101111")
2025 and 8 are the year and month, of course, and 4 specifies the 4th instance.
The string "1101111" has a 0 in the position of the day of the week you're looking for, and 1s in the other 6 positions; the first position corresponds to Monday, the second to Tuesday etc.