Right, that's the idea. Not only are these "actions" the cause of lock-ins, you also have to treat them as dependencies that you're trusting with your repo integrity, secrets, etc. As soon as you start using third-party actions you have to start worrying about https://docs.github.com/en/actions/security-guides/security-...
SourceHut is one source code hosting with the right idea here. Its CI only has the equivalent of the `run` command for running shell scripts - https://man.sr.ht/builds.sr.ht/manifest.md#tasks