Any tricks on making it be on par with Claude?

Idk how good test was that I've performed but basically I bought 100% subscription and just passed codex task to work on. I've also used "goal" feature cuz without it it's annoying as hell and stops at every random step even though you explicitly ask it to not stop. So here is the deal. I've been working on some procedural world generation on Unity, polished it quite well and then wanted to try it on Unreal, why not? Asked it to implement some set of features, okay, it did, it worked okay in terms of parity with Unity (I allowed to peek into Unity project for references). And then we came up to last step - polish the performance... I've set the goal and just allowed it to run, nonstop. Time spent on a goal was about 4 days. It fixed a couple of minor problems but major ones - circling around. Claude Opus 5.5 high did it in about 3 hours. It found a couple of bugs that were causing constant mesh regenerations which resulted in high memory allocation/deallocation which in turn was resulting in FPS spikes. So now question. How do you make it perform at least on par with Claude?