
I am trying to sort the "Status" column value by only showing "Submitted" items on the data table, but the formula isn't working
The SortByColumns doesn't work on complex column types. At least not the ones in SharePoint. Try adding a temp column and sorting by that and see if that gets you around the limitation.
Here is an example:
SortByColumns(AddColumns(Filter('Employee Activity List', Status.Value = "Submitted"), "SortByStatus", Status.Value), "SortByStatus", Descending)