Task scheduler to run tasks only during the last full workweek of the month

I have multiple tasks that need to be scheduled during the last full workweek (Monday through Friday) of every month. These will be scheduled from a Windows Server 2016 server. I cannot figure out the logic to do it.

Additional info to help: July 2020 is a perfect month to just say run on the last Monday/Tuesday/etc. Most months will not end with a full workweek though. It may end on a Tuesday and the full workweek ended 4 days before that.

I have ideas of how to do this, but they are not fully formulated:

1. Find the last Friday of the month and start 4 days before that.
2. Find the last Monday with at least 4 additional days in the month after.
3. If the last day of the month is Sunday, start 6 days before that; Saturday, start 5 days before that; etc.

What is the cleanest method to do this in task scheduler? (The scripts being scheduled are in PowerShell, though I don’t think that matters).