Is it worth looking into how Pulp plugins do this? (Every Pulp plugin has a release workflow that creates branches tags, etc. and once a tag is created, everything is automatically pushed to rubygems.org and pypi.org.
For example, all the gems here: pulp_deb_client | RubyGems.org | your community gem host
Were built by pipeline triggered here: Actions · pulp/pulp_deb · GitHub