The Festool Spare Parts catalog (EKAT) shows that part #14 is no longer available.
The part number happens to be 439919, but it is no longer available to order from Festool or places like MMToolPartss.
https://www.mmtoolparts.com/festool-stop-439919That said, with the part number, you may be able to call around to some really long-standing dealers or Festool themselves to see if there are any of these parts still lying around?
I don't know that a 3D replacement would suffice. Perhaps just some blue tape or another method to block the plunge depth? Or find a broken saw being sold for parts.