Assume router A, which is secure with up to date firmware, and router B, which is less secure, with no longer updated firmware.
I have one router connected to the net socket (internet source), and the other router connected to the first one via WAN. Each router has a different router IP address, and two separate wifi access points.
From the perspective of security, is there any difference which router "comes first", that is, which is the router that connects to the internet source and then "forwards" it?
Note: For the purposes of the question, assume no other difference in use. Both routers are accessed by devices I control and for similar purposes.