If I navigate to the Build Metadata section for my app within App Store Connect then the Includes Symbols section just says Yes, there is no blue Download dSYM button there.
The XCode build build options Debug Information Format is set to DWARF with dSYM.
So why is there no dSYM on App Store Connect?
Apple responded and said they are looking into the issue:
Thanks for letting us know! Our teams are looking into this. To stay updated on the progress and help with the investigation, please be sure to file a feedback report or contact support directly.
ASC Doesn't generate DSYM file - https://developer.apple.com/forums/thread/700051?answerId=704176022#704176022