I would like to set it for the end of the class period for each class, or maybe the end of the school day. I don't like a midnight deadline for high school students.
There is not a built-in way to do this. There is a feature idea open for this: Set Assignment Default Due Time, but Canvas has said it is not expected to affect their development right now.
If you want an immediate solution and are willing to go outside of Canvas, I did create a Google Sheet called Adjust All Assignment Dates on One Page that allows people to go through and load all of the assignments into a spreadsheet, set the dates/times using formulas if you want to set the time but leave the date, and then send it back to Canvas.
Thanks for looking into this. I appreciate it.
Retrieving data ...