We have been using this product for many years. It used to be a main station and a secondary station as described. The last ones we bought were identical, no difference between the main and secondary stations.
Here you can find a detailed comparison at ASUS: https://www.asus.com/ch-de/product-compare?ProductID=21094,14700&LevelId=networking-iot-servers-wifi-6
1. like all Asus mesh systems and routers from ASUS, the router has ASUSWRT as its operating system/firmware. ASUSWRT has convenient firewall configuration options (but is actually primarily software not hardware ;-)
2. 2x bundle consists of one XD4R and 1 XD4N model - The XD4R has two network ports and the XD4N has one network port - Mesh can be configured either by cable (preferred) or by WiFi as with all ASUS routers. The XD4R can be used as a router or access point and is usually the main device in the mesh network. The XD4N (or other Asus routers with AiMesh) can then be added as mesh satellites.
Hello, this can also be done via an existing network... I assume that the same range must be used for the IP's of the mesh nodes. (Like the existing network...)
I use these mesh points as Wifi APs.... all stations are connected with cable via existing network. (Cables laid per floor, 1 AP per floor ... )
In this regard, it is best to contact our customer service directly at https://helpcenter.galaxus.ch/hc/de/requests/new. Then your request can be checked individually.