Opus 5.5 rewrote an awful, legacy Drupal app from scratch in my preferred stack in four hours. This included handling abandoned plugins, migration to a not-insane database schema, and content fixups from a Drupal 4 backup that fixed truncated cells somewhere in a botched Drupal 6-7-8 upgrade I wasn't part of.

If you want to know everything you need to know about Drupal, have a peek at the community discussion around sitemaps. There are genuine reasons behind the complexity, but a CMS that cannot generate a list of its own URLs, leaving thousands of people baffled, is quite an achievement.