Hi! First, you should restore your PC. The hacker could use it to hack into your account again. Go to Settings > System > Recovery > Reset this PC.
Then you should try to recover your account.
You can try using the Microsoft Sign-In Assistance Tool.
https://support.microsoft.com/en-us/account-billing/how-to-recover-a-hacked-or-compromised-microsoft-account-24ca907d-bcdf-a44b-4656-47f0cd89c245
If you're unable to recover your Account, you'll need to use the Recovery forms. You can try these two forms:
https://aka.ms/recovermyaccount
https://support.microsoft.com/en-us/account-billing/guidance-notes-for-the-microsoft-account-recovery-form-4dd8fef1-33d2-4fbe-9352-66127ab9b50e
These are the methods Microsoft provides for account recovery. I have already used the recovery form, and I managed to recover my account after a few days.
- You can submit the form multiple times.
- Try to remember important personal information.
- Look for old emails that may have been sent to friends or family.
- Don't give up. The form works if you provide accurate information. If it didn't work like that, anyone could steal your account.