I think Sentebale was set up much like the Invictus Games, it was largely created to improve Harry's image in the early 2000's, just at the time Harry was in trouble with his PR.
As Taz stated, Sentebale has been in trouble in the past with suspected financial misconduct.
Dr. Chandauka was selected because (it was thought) she was a woman, a black woman and she would conform to the status quo of the "good ole boys" network at the organization. Well, so far it reads like she wasn't about to play along with either the organization or with spouting adoration concerning Meghan. I think she found continuing financial and performance misconduct and wanted to correct it. The Board and the Sussexes objected. This is all just me.
Sentebale's US donations have dropped dramatically since Harry marrying the wife. In 2023, US donations were only $500,000 for the entire year. No reports for 2024 donations. As for the polo fund raising events, donations and attendance have dropped dramatically.
The last fund raising polo match was in Singapore and it failed spectacularly. At first, the big billionaire donors bought tickets to attend because they mistakenly thought William was putting on the event, when people found out it was Harry, nearly everyone bailed out. The match was played to a nearly empty venue. I believe Dr. Chandauka until I find out more info which we may not get if the Board and Harry, Prince Seesio truly are guilty of over what she claims.