Circle-CI (https://circleci.com/ https://circleci.com/) have a macos system for building things like xcode projects. I've not tried it myself but it's cloud bas

Circle-CI (https://circleci.com/ https://circleci.com/) have a macos system for building things like xcode projects. I've not tried it myself but it's cloud based which saves self hosting. Unless you want to self-host in which case this may not be a great option.