> [build process]

I agree, the chromium build tooling is unfriendly af.

> I call bullshit

Lot of works goes into deterministic builds, have fun going down this rabbit hole: https://bugs.chromium.org/p/chromium/issues/detail?id=314403

> Now I have to trust them to keep all these dependencies up-to-date

Looks like it rolls on average every 10-20 minutes: https://chromium.googlesource.com/chromium/src/+log/HEAD/DEP...

> and I have to accept the unecessary bloat?

Ah yes, because all operating systems ship with a pristine installation of the latest pdfium.