Suppressing report sections will have no bearing on how the records are sorted. A report will always have its records sorted from the outer-most group field to the inner-most group field. In your report, the records will first be sorted by "Project", then by "RFI", and finally by "Status" regardless of what you are or are not suppressing.
If you want to choose which field to sort the report by via a parameter, then you should create a formula field and sort by that instead. So something like: if {?Sort}="RFI" then {table.RFI} else {table.Status}
but you'll need to get rid of your RFI and Status groups first.