I made my own tunnel system with a $5/mo vps that runs kernel wireguard and accepts my nas' public key. Once connected it DNATs 80/443 traffic down the tunnel to the nas, where its routed to caddy.

The vps runs a custom image that is 2.54 Megabytes. It has a custom kernel with almost everything but networking and wireguard disabled, a fixed-size fs with pre-allocated blocks and inodes to hold the vps wireguard key, and a single pid 1 binary that calls the kernel directly to set up the routing rules, generate a new wireguard key on first boot and save it to the fs, print out the wireguard public key to the console, and loops reap. Updating involves building and uploading a new image, assigning the vps to use it, reboot, wait for the public key in the console then set it on the nas so they can talk.

Very cool, do you use some kind of an atomic distro like nix or something entirely self built using Yocto/Buildroot? I do something similar with a simple SSH tunnel and a NFT rule. Though, I don’t need your kind of ephemeral setup and so I just use Debian.