If you just need a very long virtual ethernet cable between two machines, it's hard to find a solution that's easier than WireGuard. No messing about with CAs like with OpenVPN. Start with wg-quick for most setups, and take comfort in knowing that you can easily just shoving the necessary `ip [link|addr]` commands into a custom shell script if necessary.
wg ain't layer 2 like Ethernet. It's IPv[46]-only, no MAC addresses.
"I've skimmed it, and compared to the horrors that are OpenVPN and IPSec, it's a work of art"
Tailscale is based on WireGuard which seems popular on HN. It "lets you easily manage access to private resources, quickly SSH into devices on your network, and work securely from anywhere in the world."