I hope people would find this useful, I had a use case that needs users to submit a form once per week.
Showing the week number to the admin might not be the most informative, so I used these to derive the start date and end date of each week (Monday and Sunday).
Start date: Idea was moving everything to the current Sunday, then move back 6 days.
End date: Same as above, but just move everything to the currrent Sunday.
Weekday column was a simple weekday formula in a math column, taking from the timestamp.
Had to go for this since the default weekday start is Sunday (numbered 1).
Edited to fix an error in the start date.