In Numbers for Mac, you can make a custom format for this purpose.
Click on the cell to contain the result of the calculation or into which the value is to be entered.
Click the Format button to open the cell inspector.
Click Data format to open a menu of choices. Select the last choice: Create Custom Format.
In the panel that opens:

- Type the name of the format (GPS) in the Name: box
- Drag the Integer token ( #,### ) to the Custom Format box, and drop it there.
- Click to the right of the tokens in the Custom Format bar, and type ‘gpm’ or ‘GPM’
- Click OK to confirm the custom format and install it in the selected cell.
Example:
In the example, cells D2 and E2 contain the same formula, shown below the table. D2's data format setting is Automatic, so it displays the result as a decimal number with no units and no imposed limit on the number of places after the decimal.
Cell E2 contains the same result as D2, but displays it as a number limited to two places after the decimal, and labelled with the gpm unit.
On looking at that result, I decided I favoured the ALL CAPS version you suggested. Too easy to read the gps as 'grams per second' here. YMMV
Assigning custom units to values may differ (or may not be supported directly) in Numbers for iOS / iPadOS.
If so, consider creating the custom units format in Numbers for Mac, then transferring that table to iPad via iCloud.
Let us know if that transfer successfully includes the data format.
Regards,
Barry