Similarly to the Play Store, more than one build can be uploaded to the App Store Connect with the same Version Number, but the build number must always be incremented and the two numbers remain unrelated. Final users only see the version number.
While there’s a field for the build number in the Android Exporter, the iOS exporter just copies the version number and produces a binary with the build number identical to version number. This creates some confusion in case a new build must be uploaded to the A.S.C. while maintaining the version number unchanged.
It would be useful to add the iOS Build Number to the iOS exporter with the default value starting from 1, exactly like the Android exporter.