Could be also different hardware for Luci to offer a "switch menu".
Perhaps like something as this: Missing Network->Switch menu - Installing and Using OpenWrt - OpenWrt Forum
Edgerouter Lite does not have a switch. The three ports are independently connected to the CPU, like cards in an x86 box.
I think the solution is here: Setup VLANs on GL-MT6000
To setup the VLANs:
Go to Network → Devices Edit existing br-lan In Bridge VLAN filtering