Cannot change IPv4 Subnet of Router

[frollic]

TP-Link TL-WR902AC v3 no WAN interface after installation

You can set the WAN to whatever you'd like. If livebox is your other router, then you seem to have the same subnet on both sides of the WAN port, which I told you to avoid via SSH do uci set network.lan.ipaddr='192.168.10.1' uci commit network /etc/init.d/network restart now openwrt will respond on 192.168.10.1