I tried using docker for x86 builds for Lambda (which doesn't support ARM), and hit this brick wall, unfortunately: https://github.com/docker/for-mac/issues/5123

I went and checked the issue when i saw they've made a formal release but it doesn't appear to be resolved. So maybe keep it in mind if anyone has issues trying to use docker now :)

Edit: I see Docker has closed the issue and encouraged people to simply use ARM containers instead. Unfortunately that's not an option for cross-compilation when you're using x86 servers. Something for people to keep in mind when deciding what laptop to buy next, i guess.