If the Beryl AX is AP, it has no routing, the VPN, ADG, etc. will not be available (since it relies on routing mode).

Being an AP at home (to allow the 2 networks to communicate with each other) and being a router when traveling are conflicting scenarios and there is no way to simply (quickly) configure them.

For home use, if only need to access NAS, printers, etc on the main network from the Beryl side, you can also use router mode.
When you enable the VPN client, please enable the Allow Access WAN, which allows Beryl to realize that it can access the resources of the primary network, and can also use the VPN service.