I’m afraid you won’t find a board with this MCU and an Ethernet module under Mbed,
Maybe when you share which module you are using, someone might advise.
- mbed-os/connectivity/drivers/emac at master · ARMmbed/mbed-os (github.com)
- Possible/How to use a different Ethernet Phy in customized PCB than Mbed reference board? - Mbed OS - Arm Mbed OS support forum
BR, Jan