Orbi RBR750 Wifi Guestnetwork and VLAN.

Well, I am 99.9% certain that Orbi routers have no VLAN capability with the exception of the provision for IPTV, and that is a method to bypass the routers NAT facility for IPTV's.

Perhaps the 750 product is different from my old RBR50.  On my Orbi, the guest WiFi network can be set up to (a) Allow Guests to see each other and access the local network, or (b) Guests cannot see each other and cannot access the local network.  This options appears to be available only when the Orbi is in router mode.  (In AP mode, every packet goes "upstream" to the primary router and the Orbi has no ability to restrict guest access.

Although I do not personally feel that way*, I can understand that others want to isolate IoT devices. In that case keeping them from accessing the primary network makes sense.  What is the point of not allowing devices on the primary network to access those IoT devices?

* I wonder how the smart switch that turns my christmas lights on and off is going to compromise my house.  It has no camera or microphone. It has no web server. It accepts zero connections from anywhere.  Some of them are able to respond to ICMP (ping), which has been useful to me.