There is such a thing as "crossover" cable for slave to slave ethernet connections
Routers have an auto-sensing feature in them so they can do that automatically
I don't know if such a thing exists for usb, but there are usb A -> ethernet dongles,,
(and I know that in pbp these can work, connected to ethernet, then router)
maybe one on each end and a crossover ethernet cable in the middle
(but 1st I would try just regular cable, crossover cables are a bit rare)
Routers have an auto-sensing feature in them so they can do that automatically
I don't know if such a thing exists for usb, but there are usb A -> ethernet dongles,,
(and I know that in pbp these can work, connected to ethernet, then router)
maybe one on each end and a crossover ethernet cable in the middle
(but 1st I would try just regular cable, crossover cables are a bit rare)