Great day, @tberretz.
A warm welcome to you here in the Community.
As of the moment, QuickBooks Online doesn't have a way to show estimates viewed by customers.
I appreciate your idea of how this concept and functionality would be beneficial for you and your business. I will send this feedback to our engineers for future consideration in product enhancements.
Feel free to visit our QuickBooks Blog for the latest feature available in QBO.
Should you need help with anything else, please don't hesitate to write again. We're always happy to assist.