Hmm…
Tried a possible solution, but ran into a roadblock. Applying an active filter to the table prevented inserting a row below the last visible row without first turning the filter off.
Here's the example, showing both auxiliary columns (F and G) controlling what rows will be displayed when the table is filtered.
F2 contains the formula ROW() which returns the row number of the row containing each copy.
G2 contains this formula ROW()>MAX(F)−2
Both formulas are filled down to the last non-footer row in the table, and are automatically copied into a new row when one is inserted.

To insert a new row, click on a cell in the last body row (containing the most recent entry) then either press return or press option-down arrow to insert a new body row (shown above).
Columns F and G would ve hidden in normal use, giving this appearance to the unfiltered table…

And this appearance after the following steps:
- Select a cell in the last entry.
- Open the Sort and Filter Inspector to Filter.
- Click the Filter checkbox to uncheck it.
- Press return to confirm the entry in the selected cell, insert a new row and move the focus to the cell in the same column of that new row.
- Click the Filter checkbox to re-activate the filter.

Not a pretty solution, but the best I can see for now, given the apparent prohibition on inserting new rows to a filtered table.
Regards,
Barry