Hi mrnugz,
You could do either of the following:
Erase and reinstall macOS (requires an Internet connection and long download time)
- Shut down your MacBook Pro (M1).
- Press and hold the power button until it starts to load Startup Options.
- When the Startup Options window appears, select Options, then click Continue.
- If you're prompted to authenticate with your password, do so to continue.
- Select Disk Utility and click Continue.
- Select Macintosh HD from the sidebar and click Erase. Format as APFS, and click "Erase Volume Group".
- Quit Disk Utility, then install macOS.
- When the reinstall is complete, Setup Assistant will appear, which includes a migration assistant.
Use Migration Assistant
Steps 1-5 are optional. I include them here in case you gave your current account a similar name to the account you want to migrate.
- Open System Preferences -> Users and Groups.
- Click the padlock and enter your admin password when prompted.
- Create a new administrator account. Name it "Temporary" - you'll be deleting this account after the migration.
- When finished, log out of your current account, and log into the new temporary admin.
- Go to System Preferences -> Users and Groups, and delete your old user account. (Choose Delete the Home Folder when prompted.)
- Using the temporary admin, open Migration Assistant, located in Applications -> Utilities.
- Choose "From another Mac, Time Machine backup or startup disk."
- Follow the onscreen instructions to migrate your data.
- Once the migration is complete, delete the temporary admin account if it still exists.