Hey! 
I’ve implemented a working fix for using libonnxruntime in iOS distribution builds with UE 5.4. It includes:
Embedded .xcframework with bForceEmbedded = true
FORCE_ANSI_ALLOCATOR=1 to avoid allocator crash
Preserved ONNX flags (ORT_NO_EXCEPTIONS, etc.)
README with full reproduction and patch steps
Download full working project here: MinimalExample_ONNX_Fixed.zip
Let me know if you’d like help testing or tweaking. Happy to support!