My workplace disabled Opus access in June, saying that it is basically the same performance for most coding tasks at a lower cost. That might have changed now. But the main point I'd like to make is that even with Sonnet 5.5 I have a similar experience to OP - code that makes odd performance choices, is over-engineered, and arbitrarily ignores rules we put in the context. For small self-contained apps doing basic stuff it's okay. For 100k+ line codebases running fairly complex algorithmic routines it needs heavy supervision.