@Semut You can't configure a backup device, but it's a good idea to have a backup, put it on the shelf, if you need it then delete the old router from the controller, set basic settings on the new...

@O2o There is no definitive answer on how to set up a network, but you can find some information and FAQs that you can look at here. https://www.omadanetworks.com/en/

@O2o here is a guide you can look at https://community.tp-link.com/en/business/forum/topic/650256

@O2o Multiple is something called bridged vlan, it means that all vlan share the same ip network and that there is full blocking between vlan in the same bridge, bridged vlan can still communicate...

@Vincent-TP do you know where I can find 1.6.2 Build 20250908 Rel. 78163

@Rytec If you want the client to only reach one IP, add 192.168.123.10/32, for example, to only have access to 192.168.123.10.