I adore Nebula and half wish I had chosen it instead of Tailscale+Headscale, the one thing about headscale that I really like is how easy it is for users to just grab the client and then login using their gmail account and they're on the network. The biggest downside I've found to tailscale is their "network shenanigans" with firewall rules and route tables on Linux. In my testing 3-5 years ago, Nebula worked great in my test environment.

I'm tempted to add Nebula support to WeEncrypt for automated handing out of the certs using a LetsEncrypt-style short lived certs. I could even imagine a fairly easy to build workstation client that would require end-users to login to get their refreshed certs once they expire, like we do with Tailscale+Headscale.

That would dove-tail nicely with the existing TLS and SSH signed host keys support. https://github.com/linsomniac/weencrypt