How do i completely delete my account, profile etc, everything?

Hello martperformance-,

I'm sad to learn you're looking to cancel your account and delete all your data. I also respect the importance of being able to make the best decision for your business. Feel free to elaborate more about what influenced you to make this decision. I'm here to help you get back on track with your work. 

In the meantime, you can cancel your account by following the steps in this article here. You can delete the data on your account only if your account is under 90 days of usage since the date you started your subscription. If your account is within 90 days, please follow the steps below to delete your data:
 

Important note: This process will delete all the data in the company file. Once you delete it, you can’t restore it. This process is only available to QuickBooks Online Plus, Essentials, and EasyStart. 

1. Log in to your QuickBooks Online Company.
2. Change the URL to include /purgecompany
   Example: Change https://sg.qbo.intuit.com/app/homepage to https://sg.qbo.intuit.com/app/purgecompany
3. The next screen will provide a summary of the items to delete. Type YES to delete the data, then select OK.

I encourage you to check out this article here for more info on how the above process works. If your account is outside of the 90 days, you can cancel your account and your data will remain on your account for 1 year. You can still access the data as read-only access. After the 1 year is up, your data will be deleted. You're more than welcome to ask additional questions, I'm here to help you reach your goals with ease.