I can see you're trying to add payment method for each vendor so it will show on the reports @acarter16. I'd like to provide some insights and tips about it.
You may or may not be able to enter the payment method depending on how access roles are set up in QuickBooks Desktop. I suggest reviewing the account's roles and permissions to ensure you're not restricted from doing such.
Additionally, the option to input the payment method in the Bill or Enter Bills page is currently unavailable. However, you have the option to select it from the Pay Bills area.

After that, you can customize the A/P Aging Detail Report by adding Pay Meth in the Filters tab. This enables the payment method column to show on the report. In case it doesn't display the payment information, you can click on the bill manually to access other details. Otherwise, export the report to Excel and review the information from there.
The Vendor Balance Detail and Transaction List by Vendor reports will also show the desired information as long as you perform the same customization to both of them.
Once everything is in order, you can browse this module about fixing account balance differences in QuickBooks: Reconcile an account in QuickBooks Desktop.
You're always welcome to comment back in case you have additional concerns or queries about this matter. It's our pleasure to be of help. Have a good one and take care!