Managing personal Outlook.com account settings, security, and privacy
Hi ,
I'm Dyari. Thanks for reaching out. I will be happy to assist you in this regard.
Recovering your account is a good first step, but hackers sometimes leave things behind, so they can access the account again. Please sign out of all devices from your account security page. Also, make sure the recovery email and phone number are yours.
Then, check email Rules or Forwarding and remove anything suspicious. Review connected apps and remove any you don’t recognize.
As for the undeleted folders, try deleting them from the Outlook web, as it sometimes works better than the Outlook app.