Creator of Cicada here. I mentioned this in another thread, but I have an experimental "GitHub Actions to Cicada" converter tool I'm working on that makes it easier to import GHA workflows to Cicada. GitHub already has an importer tool to import other git providers to GHA, but of course they don't have any export features.
Like you said, there are lots of intricate details you need to get right, and each CI/CD provider has a different ethos about how CI should be done. What I'm trying to do with Cicada is create one workflow format that gives you the power of GitHub Actions with their numerous event triggers, but make it work for other providers like Gitlab. Having one format that works with many providers is better than converting multiple formats back and forth, IMO.
Like you said, there are lots of intricate details you need to get right, and each CI/CD provider has a different ethos about how CI should be done. What I'm trying to do with Cicada is create one workflow format that gives you the power of GitHub Actions with their numerous event triggers, but make it work for other providers like Gitlab. Having one format that works with many providers is better than converting multiple formats back and forth, IMO.