Reproducible Guix builds
Bitcoin Core uses the Guix package manager to achieve reproducible builds. Carl Dong gave an introduction to GUIX via a remote talk in 2019, and also discussed it further on a ChainCode podcast episode.
There are official instructions on how to run a Guix build in the Bitcoin Core repo which you should certainly follow for your first build, but once you have managed to set up the Guix environment (along with e.g. MacOS SDK), hebasto provides a more concise workflow for subsequent or repeated builds in his gist.