Good morning all!
I'm trying to have a formula calculate two selected values from a PowerApp that populates a SharePoint list: Primary Date and Alternate Date.

Here is my current formula:
"Number of Participants Currently Enrolled For Your Selected Date: " &
With({_items: Filter('North Campus Walking Tour Signup Tracker', 'Primary Date'.Value = DataCardValue4.Selected.Value)},
CountRows(_items))
It works well for the Primary Date, but for the alternate date, I can't get it to calculate correctly:
Number of Participants Currently Enrolled For Your Selected Date: " &
With({_items: Filter('North Campus Walking Tour Signup Tracker', 'Alternate Date'.Value = DataCardValue4.Selected.Value)},
CountRows(_items))
I get the following error:

Lastly, I'm building an "admin view" for people that sign up, but since I can't get the Alternate Date to calculate correctly, the formula doesn't show the correct number:
Sum(
With({_items: Filter('North Campus Walking Tour Signup Tracker', 'Primary Date'.Value = "1 September")},
CountRows(_items))
&&
With({_items: Filter('North Campus Walking Tour Signup Tracker', 'Alternate Date'.Value = "1 September")},
CountRows(_items))
)
The error for this formula is:

Any thoughts on how to correct the formulas? Thank you!