Hello, I need your ideas to try to solve a technical issue.

I live in a house A, where I have a fiber optic internet connection and a DECO X50 Mesh network. This DECO is correctly configured with a WireGuard VPN server, and I can access it remotely without any issues thanks to TP-LINK’s dynamic DNS, after properly setting up port forwarding on my fiber modem.

In house B, where my parents live and often need technical assistance from me, there is a 4G+ router provided by the local operator, along with another DECO X50 Mesh network that I can manage remotely via the DECO app.

Now, the issue is that the 4G operator uses CGN (Carrier Grade NAT), so the WAN IP address of the router does not match its public IPv4 address. My operator does not yet provide IPv6, and the 4G router does not offer any remote management capability.

I wanted to set up a VPN server on the DECO at my parents' residence to access the 4G router remotely if needed, but this is impossible due to CGN (no port forwarding or domain name possible).

I have thought about and successfully configured a VPN client on DECO B to access DECO A. From a PC connected to DECO B, I can access the network resources of DECO A.

The question: if I am connected to the network of house A, is there a way to access the web interface of the 4G router at my parents' residence with this configuration ?

Thank you very much, any suggestion is welcome !