same issue, basically, our company upgrade SonarQube to 7.9 enterprise from community, we were using backelite-sonar-swift-plugin with slather to upload coberura code coverage report to sonarqube, after upgrade, it replaced backelite-sonar-swift-plugin with SonarSwift and can not upload cobertura xml report. there was a link to generate generic coverage data ([Coverage & Test Data] Generate Reports for Swift) but this script is not updated for a while and I cant run it from either local or jenkins server.
I moved your post to a new thread, even if your symptoms are similar not necessarily the problem is the same.
I see that you moved from community plugin, but which steps did you perform to generate report? what’s not working when running the script we suggest? (it was updated in october to support XCode 11, so it is supposed to work).