Check if date exists in Named Range "Holiday_List"

In my Workbook_BeforeSave
I am looping through a range (T2:AM50) looking for bad entries (Weekends and Holidays).
All these entries are dates (or empty).

To check for Weekends, I have used:

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BUT I need to compare against the NamedRange "Holiday_List" also.

Additionally, I'd like "Holiday_List" to span more than 2 columns but can subdivide into two lists if necessary.


I know there is a Networkdays option, but cannot figure out how to apply as there is no Start/End Date there are just dates entered randomly into the cells in T2:AM50.