If you use another cell to enable you to record the number of extra
days to omit, eg in A1, then your formula could be amended as follows:

=(TODAY()-1-A1)

If A1 is blank or zero it will act like your current formula. If it is
Monday after a normal weekend, enter 2 into A1. If it is the first day
back after a 4-day holiday, enter 4 in A1. And so on.

Hope this helps.

Pete