Legacy Open Mesh: Does the G200 router support load balancing?

No, the G200 router does not support Load Balancing.

To be more specific, the router cannot support any feature which requires the use of both WAN ports at the same time. This is due to a hardware limitation which only allows one of the two WAN interface to ever be active at one time.

The G200 router has two physical WAN ports, however, these two physical ports connect to a single internal interface. This means that only one of the two WAN ports can be active at any given time. The second or "inactive" WAN interface will show no Ethernet link at all since the physical port will be disconnected from the internal interface. This is why load balancing or other active/active use cases are not possible on the G200.