In my experience, communication protocols are purchased as needed and are not included with the basic instrument.  So there's no hardware/firmware connected to the terminals unless that comm module was ordered originally or added after delivery.

Check the model/order number on your unit to see if the associated order code appears.

According to page 3 of the FMT020 catalog sheet here:

https://support.industry.siemens.com/cs/document/109847376/catalog-sheet-sitrans-fmt020?dti=0&lc=en-WW

Modbus RTU/RS485 uses order code F04
Modbus TCP uses order code F10

Modbus/TCP would use an Ethernet connection, same as Profinet or Ethernet/IP, but the manual wiring diagram that you show does not list Modbus/TCP with the other Ethernet protocols, so it's up for debate whether Modbus/TCP is actually available whether it is vaporware.