I have a vacation home with an OpenWRT router behind a LTE modem (CGNat) and I would like to access the network from outside, preferably through VPN (Wireguard) but I cannot duckdns the dynamic IP address as it is behind CGNat.

Which is the cleanest way to achieve this? I discard the use of an intermediate VPS server. Maybe open a SSH tunnel to a router accesible from outside? How would it be the procedure?

Thanks in advance.