Configure them both locally and ensure you have a connection before you move the pi to another country
If you're behind a CGNAT on one network, that'll change some things. That network will have to be the client.
(If both are behind CGNAT, you're out of luck and cant use this - will have to be tailscale or other method)
If using a domain name make sure its always pointing to your ip (in case it's not static)
I think if you set allowed ip as 0.0.0.0/0 on the client it'll route all traffic.
Raspberry Pi:
MiniPC:
Points to note:
Configure them both locally and ensure you have a connection before you move the pi to another country
If you're behind a CGNAT on one network, that'll change some things. That network will have to be the client. (If both are behind CGNAT, you're out of luck and cant use this - will have to be tailscale or other method)
If using a domain name make sure its always pointing to your ip (in case it's not static)
I think if you set allowed ip as 0.0.0.0/0 on the client it'll route all traffic.
Edit:
Saw your comment about just having qbt use the vpn. Check this guide out