I use wireguard. One network is behind cgnat so i just get that client to connect outbound to the other client to initiate the tunnel (instead of trying to connect to IT) and it works just fine.

I did try tailscale once upon a time but it was so clunky and confusing for me…i just wanted to simply access my entire networks remotely without any overhead

Came here to suggest this. Glad its getting the exposure it deserves

Im oldschool and use Gnucash

So many different questions here. However…

A knife can be used to kill but also cook a nice meal.

I think they mean powerline adapters

I have joplin but personally found myself using Nextcloud Notes 100% of the time. I just need very basic, quick markdown notes

Ticks all your boxes

Raspberry Pi:

1. Install wireguard (as a server)
2. Set up a peer/client config
3. Open wireguard port on the router

MiniPC:

1. Install wireguard (as a client)
2. Add server config and connect to server
3. Verify connection
4. Ensure connect on boot

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