Question about TP-Link Deco BE65 (2-pack)

No, this is the V1 version.

I bought this model in a duo pack. It works as described. Unfortunately, the basic installation is only possible via the app. After a successful installation, further settings are possible via a web browser. Unfortunately, I have not yet succeeded in migrating to an existing Wi-Fi network (TP-Link Archer BE 800, or Swisscom Internetbox 4). I assume that it must be my fault or that the systems are not compatible at the moment.