I'm not sure if there are any single good URLs I can give you. The best way to learn is to read the chromiumos repo and see how they build the image, how they collect and deploy profiles, etc. You can also look at the mailing list of clang-built-linux to see how their kernel is built with clang and how they integrated that with their profile pipeline.

In the end though it is cultural and not technical. Debian will bend over backwards to make sure That One Guy can still install the latest version on his old Centaur CPU, from floppies. ChromeOS is laser-targeted for specific, allow-listed hardware platforms. If you are philosophically committed to the eternal comfort of That One Guy, the Debian way makes more sense. If you just want software that's faster and more secure, ChromeOS has the better way.