Cannot ping router on a different subnet from WAN IP
So I have a system set up sharing internet to a several buildings on my property. I have the internet from the ISP connect to an Archer A10 with a public WAN IP and the LAN 192.168.0.1. Five routers are connected to it with their own subnet.
Router 1 (Archer AX21): WAN IP 192.168.0.2, LAN 192.168.1.1
Router 2 (Archer AX21): WAN IP 192.168.0.3, LAN 192.168.2.1
Router 3 (Archer AX10): WAN IP 192.168.0.4, LAN 192.168.3.1
Router 4 (Archer AX10): WAN IP 192.168.0.5, LAN 192.168.4.1
Router 5 (Archer AX10): WAN IP 192.168.0.6, LAN 192.168.5.1
From a PC on the main network with IP 192.168.0.10, I am able to ping routers 3-5 with their WAN IP, but not routers 1-2. All routers have Ping from WAN enabled in their settings. I also set up a port forwarding entry to create a routing protocol between each router and the main router in both directions. Any explanation as to why I can't ping those two routers?