There are also a few Hugo templates for vanity import paths.

Here's mine: https://github.com/foundata/hugo-theme-govanity (e.g. used at https://golang.foundata.com/ )

And yes I'm aware of the irony of hosting this on GitHub... still figuring out a good workflow for maintaining our OSS on Codeberg and GitHub in parallel fed from the internal forge. The dependency on our own domain is real but we favor it.