I've used the orjson 3.10.18 patches as a base to get orjson 3.11.3 working under GraalPy 25. I don't know how to turn this into a patch on the source wheel (1. due to an entire dependency upgrade 2. due to me not really being a Python developer), so I'm leaving my work here for someone who knows what to do with it. File was generated with git diff.
orjson-3.11.3-patches.diff