Nebula looks great for server-to-server connections for things like administrative management/control or the like. The fact that it's fully free means we would

Nebula looks great for server-to-server connections for things like administrative management/control or the like. The fact that it's fully free means we wouldn't have to deal with licensing, unfortunately I can find it hard to get approval for licensing and purchasing. I like ZeroTier because: It was dead simple to set up, the web management UI is good, the "public" networks seemed like they might be nice for CI/CD servers to connect into some infrastructure to deploy (though that didn't work out because CI/CD docker didn't have flags allowing ZeroTier to work, but I did just get SSH over userspace ZeroTier working). It's super easy to set up in all the environments I've looked at.