How to Auto-Fill Check Image Descriptions?

Well, it should be explained that a Bank Statement for checks means you are looking at the date the payee cashed it. Not the date your client made those payments by issuing the checks. Only electronic payments are timely to the statement clearing date. So, you already have manual adjustments to make, to get these expenditures in the proper period.

Next, when you describe using Accountant Login, and yet the source data is Bank. You want to pull the data from Bank, so that it includes all data fields they provide. You have the statement, so there are pdf reader or other ways to merge Excel data into your file, before import. You seem to be stating it doesn't show in the QB Bank Feed. That is up to the Bank, which is the financial partner to Intuit in support of QB.

Lastly, I've have US Bank as a client, in support of a QB for Mac user, and the bank was not sending description (check memo) in their OFX data stream. It's up to the bank, following OFX, which is an open standard.