I'll answer this query for you.
The option to disable the Use display name feature for all vendors at the same time is unavailable. You'll have to go through each vendor and toggle the feature off. I can see how this feature can be a handy addition as a feature to the product. With that said, we'll take note of this idea.
I suggest you visit this page: The QuickBooks Blog. It lists new features and improvements each month. For October, we have the Reclassify Transactions available for QuickBooks Online (QBO) Advanced, as well as the integration of Bill.com to QBO Advanced.
Tag me in the comments below if you have other concerns. I'll get back to you as soon as I can.