I am using Xcode 26.4.1 (17E202).
To copy the dylib, I am using a custom made Xcode build phase. I opened the resulting IPA to check, and the .dylib is present in Payload/AlbusAir.app/Frameworks/libswiftCompatibilitySpan.dylib. I put it here because the ITMS-90429 error told me that the file is expected in /Payload/AlbusAir.app/Frameworks.
I checked the thread that you linked but I don't see any useful answer made to the OP, did I miss something?
Thanks for your help !
Topic:
App Store Distribution & Marketing
SubTopic:
App Store Connect