This is a huge bummer.  I cannot open my online scheduling (and thus take cards for a cancellation policy that I would like to implement) because it takes FOREVER to keep changing my hours.  I may have to find a different scheduling program that allows me to do this. 

Hello @anniewolka! Welcome to the Seller Community.

Yes can customize your availability by specific date - check out this Product Udpate for the steps: Square Appointments Update: Override Hours and Any Available. The downside is that you do have to manually enter days/hours for each week. Take a look at the post and try out the cutomize availibility feature, if you have any questions please let me know! 

Where is the ‘staff view’ drop down mentioned in the help article?

@anniewolka From your online Appointments Calendar the dropdown will be at the top of the screen in between the Week/Location Name options. Before you select it it might say Only Me.