While I do agree with your parallels between Diana's and H's behaviors, IMHO, the situation the RF is in from a PR standpoint is different with a dead Diana versus a living H.
Diana's reckless behavior was in the process of damaging her reputation, but her sudden death stopped all negative UK headlines. A newspaper had to recall its "Sex-crazed Diana" newspapers the day Diana died. Without Diana around to destroy her own reputation, combined with Mohammed Al-Fayed's and Charles Spencer's accusations (despite Al Fayed's driver and security failing Diana and Charles Spencer having introduced Bashir to Diana which ultimately resulted in Diana rejecting RF security), the RF were in an impossible situation.
By contrast, H's reckless behavior has damaged and is continuing to damage his reputation, generating constant negative headlines in the UK. H&M's reputation is toast in the UK. And H&M's target USA market has not been backward in presenting its increasingly negative view of H&M:
-"Disaster tourists" from a celebrity
-"F*ing grifters" from employer Spotify
-"No talent at all" from a talent agency head
-"Dictator in heels" from Vanity Fair.
-"Dumb prince and his stupid wife" from South Park.
IMHO, all the RF needs to do is continue to grey rock H.