oh it was with buildx (which uses qemu) as GitHub Actions run in x64. I was showing a specific example of arm64 build tooling challenges small startups encounter (Github Actions lack of arm job runners in this case). My arm64 builds on arm64 architecture scream.
You can do a self hosted runner on arm though, even on a Raspberry Pi (if inclined), so not sure it's prohibitively expensive to a startup, could even afford a spot graviton :D
I've got to say though, I've not experience that delta in build times, even emulated on my machine.
