This isn't a POC web engine; it's throw-away code that can never scale to a full web engine.
So instead of wasting millions on this autonomous run, they should have put together a small team of people with some ideas on how to improve on existing web engines, and then give that team a large token development budget. You could get a nice POC after a couple of weeks, and after a year or two of further iterations you might have something really interesting.
So this is a great example of how AI fails when left unsupervised; a more interesting experiment would be about how a small team can leverage AI to leapfrog Chromium; not in one week but in a year or two.