If your app is not too large you can do CI/CD perfectly fine from your laptop. Put it in a docker container if you want to ensure it is perfectly reproducible. You still need Github as the origin repo to pull from, but the "git part" of GitHub seems to be (almost) always up and running. (We use "capistrano" for this)

> If your app is not too large you can do CI/CD perfectly fine from your laptop.

Not if you want to make sure it compiles and works on Windows (which you don't have) or macOS (which you don't have and can't emulate). That's something github gives for free, and for me, it's the only reason to stay on github for small/tiny free software projects (at least as a secondary host).