Lan Bridge to set up BufferBloat appliance between main router and modem

I have found I run into connectivity problems when I allow my LEDE router (Netgear R6300v2) to do my PPOE login. This problem is footnoted below*

So what I would like to try is to create a lan to lan link on the LEDE router in such a way that luci-app-sqm can be applied to one of the physical settings. In this way the router will be transparent and my PEPLINK router can make the PPOE connections.

Since the R6300v2 has 4 lan connections and one WAN connection, I visualize this as not using the WAN connection at all and, instead the connection to the modem going into one Lan connection and the connection to the PEPLINK going to another Lan connection.

I have been using the Luci Lua interface and find doing so helps my visual understanding of what the LEDE router is doing (as a newb)

So I think something like this would be needed under Network -> Switch

LAN 4 is turned off under VLAN 1 and turned on under VLAN 3

Then a new interface might need to be made like this (mac addresses deleted):

Of course I may be completely wrong about this as it is not working at the moment and a connection between LAN and LAN2 has not been made and if one is made I'm not sure luci-app-sqm could be effectively applied to one of the physical settings. As I understand it the entire array of lan connections and wan are on a single switch in the R6300v2 so functions and connections of the switch are controlled completely by the VLAN settings on the switch.


footnote*

I am attempting to put LEDE project routers between my PEPLINK 380 and my transparent bridged modem. The reason for doing this is to control bufferbloat. In this position the bufferbloat protocol (luci-app-sqm) can be applied to each of the 4 WANs. The WANs are all DSL+ links at nominal 10 mbps supplied by CenturyLink.

I can do this in a configuration with the LEDE router connecting to the modem and supplying the PPOE connection. The LEDE router is then connected to the PEPLINK 380 via a static IP. DHCP is turned off on the LEDE router. DNS is cached in the PEPLINK. When I go to Status -> Real-Time on the PEPLINK it shows appropriate activity download and upload on the WAN where the LEDE router is connected.

This works fine with one LEDE router connected to one of the WANs on the PEPLINK. Additional LEDE routers populating the remaining WANs make it more and more difficult to connect to web pages, the connection may never connect etc.