How can I get QB to accept a payroll check dated in Dec 2021 regardless of the tax penalty?

Glad to see you visit the Community, @reidbthomas.

I'm here to help you with historical payroll concerns.

Please keep in mind that you can only enter payroll from the current year in QuickBooks Online because it is a cloud-based storage system and we only maintain payroll records for the current year. Having said that, kindly follow the steps below:

1. Open the Workers menu from the left pane then select the Employees page.
2. Choose the employee, then click on Enter prior pay details. 
3. Fill in the necessary information.

For more information about the process, read this: Set up a prior payroll for QuickBooks Online Payroll.

In addition, since you're dealing with payroll from previous dates, I recommend contacting our Payroll Support. Alternatively, you can speak with your accountant about this to ensure that everything on your records is in order.

You're always welcome to post if you have other concerns about payroll or QuickBooks in general. We're here to back you up. Have a great weekend!