Setting a static route for a specific network adapter with two network adapters

Solution 1:

Part of the problem is that you have 2 DEFAULT GATEWAY which violates the meaning of DEFAULT GATEWAY. Put the default gateway only on one interface. Then with static route, direct the traffic you want to go via the other interface.

For example, LAN1 192.168.123.13 Mask 255.255.255.0 and GW 192.168.128.254. That will get all traffic to 192.168.123.x and anything to any other network will be directed through the gateway.

But then add LAN2 192.168.137.15 Mask 255.255.255.0 WITHOUT any default gateway. That will automatically create a routing entry that 192.168.137.x will go through this interface instead of the Default Gateway. Now, if you want other traffic to go through that interface, you can create a static route like:

ROUTE ADD -P 192.168.33.0 MASK 255.255.255.0 192.168.137.1

That will send the traffic going to 192.168.33.x through LAN2 as 192.168.137.1 is in the same network as LAN2 interface.