Fixed for us too, thank you! I will close this issue if I can

Opened here https://feedbackassistant.apple.com/feedback/22177166 FB22177166 ("Testflight is currently unavailable" message for all users/ all app version/ builds)

I had the same experience using altool to validate an .ipa as part of our CI/CD process (xcrun altool --validate-app), it started failing with the same " AttributeError: 'BuildEnvironment' object has no attribute 'sdk'" errors. Just for debug purposes, it actually runs successfully if the .ipa is valid, but crashes if the .ipa is not valid, instead of returning a real validation error. Upgrading to Xcode 14 does fix the issue.