> To maintain a fair comparison, GitHub has supported self-hosted runners for several years

Yeah, tried that first, as I didn't want to move to Forgejo, I just wanted to keep working when I wanted to work.

The GitHub runner on Linux seemed fine, but the ones for macOS and Windows seemingly did something that made them a hell lot slower than even running VMs and then executing stuff inside those. I'm not sure what the runner is doing, if there is some built-in sandboxing or what not for those platforms, but it wasn't feasible to rely on for me as the builds took way too long time.