UPDATE: I have an another router Archer C6U v1.0 Firmware version 1.0.7 Build 20230829 rel 53730(4555) I replaced the C1200 with the C6U, did the same settings an it appeared in the system routing...

Hello, I have the Archer C1200 as my main router, connected to my ISP's router which is set to modem mode. It has LAN configured as 192.168.0.1 with subnet mask 255.255.255.0 so my devices have IP...