If Epson Scan 2 only shows flatbed options, the scanner usually isn’t detecting the transparency unit in the lid.

Things that have helped:

• Remove the scanner from macOS "Printers & Scanners," then add it again so the driver reloads.
• Reinstall Epson Scan 2, then power-cycle the scanner: turn it off, disconnect power briefly, open the software, turn the scanner back on, refresh/detect the scanner, and reselect it.
• Check the lid-to-base connector. On these Epson flatbeds, the transparency backlight is in the lid. If that connector is loose or dirty, the scanner behaves like a normal flatbed and the transparency option disappears. Reseat the connector firmly; a little compressed air in the socket may help.

In short, this is typically a driver/device-detection issue or a physical lid-connector issue, not a film-setting problem inside the scan dialog.