I have consistently heard the opposite.
Actions has more polish but is not as feature rich is what I have heard.
What’s nice about Git as a distributed VCS is I can use both GitHub and Gitlab and get the best of both worlds very easily. I win either way, and neither can lock me in (you know Microsoft would do it if they could, but they can’t). Therefore we see actual legitimate competition, where one has to constantly improve to outdo the other. I wish more things worked that way.
That's true for the core git piece, but if you're a big enough org the CI/CD features, or issues, or pages, etc, could effectively lock you in.