While it’s not perfect, GitHub Actions was pretty straightforward to set up for an open source iOS project I help manage[0].

Most of the actions were pre-existing Makefile targets used during the bootstrap process anyway, so the YAML config was fairly lightweight.

Echoing the other comments in the thread, the docs did feel a bit sparse when I last poked around (this was back when Actions was still in beta).

[0] https://github.com/birdrides/mockingbird