> If your CI can do things that you can't do locally: that is a problem.

Completely agree.

> I'm a huge fan of "train as you fight", whatever build tools you have locally should be what's used in CI.

That is what I am doing, having my GitHub Actions just call the Make targets I am using locally.

> I mean, at some point you are bash calling some other language anyway.

Yes, shell scripts and or task runners(Make, Just, Task etc) are really just plumbing around calling other tools. Which is why it feels like a smell to me when you need something more.