If you go into the whistleblower's complaint and remove everything that is not his firsthand account there's shockingly little there around bribery. I do think that this individual has an HR legal case for being mistreated based on their writing but that has little to do with the alleged bribery. Reading an audit report that they didn't pen doesn't mean much and the findings could have been made right without their knowledge. Nobody goes back and marks findings on an original audit report 'fixed.' There is also a lot of jumping to conclusions. The only thing in the whistleblower post that I can see that they provided as concrete issue that they were firsthand involved with was a sum of $40,000 which is a great distance away from the $200 MM they are suggesting. If it was as prevalent they would have multiple transactions they were directly aware of and the sum would be much higher than $40,000. There is an assumption laden in the article that the only outcome for any discrepancy are bad actors enriching themselves instead of negligence or incompetence. Bringing in other cases where Microsoft was fined is irrelevant for the purpose of their whistleblowing, nobody cares about the other crimes we already know about we care about the crime you saw.
Too much of this sounds like a jilted employee on a PIP and not enough of it was just straight facts and clear cause for action. You don't need to craft a narrative, just whistleblow on what you saw.