Hello there, Blackoutfab.

I know the urgency to categorize your transactions correctly to keep your accounts up to date. Let's modify your transactions by batch so you'll not go through each and every single one of them in your register.

With your expense transactions, you can visit the Expenses menu. You can filter the transaction you want to update, then categorize them.

1. Go to the Expenses menu.
2. Select Expenses.
3. Click the Filter drop-down.
4. Choose the Type, Dates, and Category.
5. Select Apply.
6. Choose the transaction by clicking the box beside the Date column.
7. Click the Batch actions drop-down arrow, then select Categorize selected.
8. Select the correct category by clicking the drop-down arrow in the Categorize Selected window.
9. Click Apply.

I've attached screenshots below for your reference.

Moreover, categorizing your sales transactions by batch is currently unavailable. You can pull up the Transaction Detail by Account report for the complete list.

1. Go to the Reports menu.
2. Type Transaction in the search box, then select Transaction Detail by Account.
3. Select the Customize button.
4. Set the Report period in the General section.
5. Select the Filter drop-down, then click the box beside Transaction type and select the transaction by clicking the drop-down arrow.
6. Click Run report.

From there, open the transaction manually by selecting it and update the category type.

You can save the report you've just customized so you can quickly run it in the future, kindly refer to this article for the steps: Customize reports in QuickBooks Online. It also contains information on how you can send it by email on a recurring schedule. 

I'd also recommend reconciling your accounts every month. This way, you'll be able to detect discrepancies early and make sure your books are accurate.

Please let me know if you have other concerns. I'm just around to help.