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(I have used Reserved LAN IP addresses by MAC, Individual devices are given custom names, Website filtering, AI Protection Pro, Adaptive QoS which is customized etc. Configuring ASUS RT-AX92U in AP mode will make the OpnSense appliance or computer see each device directly but I will end up losing some features of ASUS RT-AX92U in AP mode. This way, the ASUS RT-AX92U router sees each device directly. My ASUS RT-AX92U is my main router on a separate network segment (as its WAN port is connected to ISP router LAN port) with one mesh node and couple of access points attached to ASUS RT-AX92U router.
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As far as I know AP mode makes some of the router functionality not usable. I am tempted to use OpnSense due to the superior feature set but as you have mentioned the router has to be configured in AP mode in this case.
