Hi,
Welcome to the community!
IIRC the report format is binary; you’re going to have a very hard time producing a report outside of analysis.
For an analysis-produced report, I’m not familiar with the details, but if I drill into the .sonar/scanner-report directory in the Jenkins workspace of a recent job, I find a number of files which probably comprise the zip that’s sent at the end of analysis.
Good luck!
Ann