In IP>Services, you can change the port WinBox uses. Change it to something else (I used 8292) then
enter the WAN IP of the router followed by the port # in the WinBox login like so:
xx.xx.xx.xx:8292
(above is only an example)
Give all your routers a different port # for the Winbox service.
You don’t necessarily have to change the port that winbox is listening on. You could just have a different port mapped from your tplink router, assuming you’re doing some kind of port forwarding/translation, e.g.