Last i know was that rpi‘s can barely handle one gig but not the effectively two for duplex. Not to mention that the ethernet port (singular) runs over usb

On the last pi, the eth port is on a pci express bus. For routing usage, you will need to either have to add a usb3-eth adapter or run "router-on-stick" with a single eth port and VLAN.

Or, you could also look at the NanoPi R4S or upper model with multiple eth and 1 Gbit capable SQM.