Would like to see the option of grouping data by days of the week. (Sun, Mon etc…)
I think there is not one. Except you can and add a column to your data with the day of the week.
Yes, use Helpercolumn with =TEXT(A2:"NN")
Yeah I already know about the the adding extra column. The adding an extra column is a kind of clunky way of doing this. Much neater and cleaner way is an added option to group in this manner.