Never open ports to the internet unless you want everybody to see it. Always use VPN to access your selfhosted stuff. If you’ve got a lot of VPN connections to set up, try generating a QR code for the connection. Makes it a bit faster to setup the client.

We have similar problems with foreigners all the time, when they decide to climb mountains with flip flops and sandals, without much preparation and then they have to be rescues with helicopters.