In practice the public CAs didn't quite work out. www.cacert.org tried it, and was interesting, but didn't work out in the end. Especially now its a bit of a joke with the login page on http and the website certificate not being cross-signed, so you have to accept them explicitly.
Looking forward to using this.. Although in my case the source of thruth wouldn't be openpgp keys but perhaps wireguard keys to our vpn or maybe omemo or ssh keys.