I understand how valuable your time is, @whereismyprofile.
I'm here to shed some light on the QuickBooks QR code.
The QR code can only be viewed when viewing the invoice in the Print Preview window and when sending it to your customer. Viewing it on the invoice page isn't possible.
Moreover, steer away from errors, please ensure you're using the Airy new template and your Online payments are enabled. This way, your customer can view the QR code when paying the invoice. 
You can also refer to this article for more details about QR codes in QBO: How to use payment links in QuickBooks Online.
Once your customers' pay their invoices, you can utilize these links for reference on how to handle their payments:
I'm all ears if you have any other questions about QBO QR codes. Just add the details in your reply and I'll take care of it for you. Stay safe and have a good one!