I would like to deactivate a Tax group I have created or even delete it, since i have made one or more of the rates within the group inactive. How do I do this?

Glad to have you here in the Community, @bplodge.

Once the group tax created, it can't be inactivated or deleted. At this time, we can only inactivate individual tax rates. Let me guide you how.

1. Click the Taxes from the left menu.
2. On the Tax center page, select Edit rates from the Edit drop-down.
3. Select the tax rate you want to inactive.
4. In the Action column, click the Edit drop-down and select Make inactive.
5. Click Yes to confirm.

Here's an article you can read for more details: Remove a VAT or GST rate.

You might also want to check out this article to learn more about GST/VAT rates: How do I set up sales GST/VAT rates and use them on forms? (International QBO).

Please let me know if you need clarification about this, or there's anything else I can do for you. I'll be standing by for your response. Have a great day and stay safe.