Need help/tips for vpn setup, double NAT

[BENROFU]

Hi
My setup (on a ship) is:
One Zyxel NR7102 5g modem with ip passtrough to a edgerouter x with openwrt installed. The openwrt router is for splitting up for multiwan, and several vlans.

On one of the vlans, is another edgerouter with gargoyle 1.14.0 connected.
This is for dhcp and monitoring one of the "crew" networks with several wifi accesspoints installed.

I am now in posession of a simcard with unlimited dataplan, but from another country. Roaming is activated on the zyxel works fine, but now i got a new issue. Wifi call does not apply because the mobile providers thinks i am in another country. I have read a bit of same issue of starlink users that sails to diffrent countries.

What am i thinking: Is it possible for me to connect the gargoyle to a VPN server in the country where our mobile subscriptions is registrerd ? I do not want to use vpn service for the other vlans on the openwrt router, thats why i ask if its possible on the gargoyle wich is "closest" to the mobile devices.

Can someone with experience please share som info if this should be possible, and maybe som hints ho to, to reduce downtime?

[ispyisail]

thats why i ask if its possible on the gargoyle wich is "closest" to the mobile devices.

I don't know what this means.

Can you draw a network diagram?