Instead, we ship with our own debian repo, hosting graciously provided by CloudSmith https://caddyserver.com/docs/install#debian-ubuntu-raspbian. This is packaged via CD with GitHub Actions, and you can verify the authenticity of the build since it's signed by Matt Holt's GPG key.
For RHEL, it's in COPR, and that's the best you'll ever get for similar reasons https://copr.fedorainfracloud.org/coprs/g/caddy/caddy/