[babagabooj]

What about Slack's Nebula? Tailscale is not fully open source. I believe there is also headscale which is attempting to replace the closed-source parts of Tailscale. But I am curious about Slack's Nebula. Has anyone used it for anything like this?

[vineyardmike]

Never used it, but it seems more complex and doesn't use standard tunneling (eg. wireguard).

You should also check out Innernet if you're interested in this space. Wiretrustee is similar to TS in that it mixes OS/Closed source.