Hi Simbi,
Thanks for posting in the Community!
It's a great idea to be able to customise the rows/columns in the Budget vs Actual report in QuickBooks Online. However, the option is unavailable in the current features offered at the moment. You'll have to run different reports and filter the reporting period.
I can see how helpful this is for your company, I'll make sure to add this to our report and let our product team know.
However, there are different report that has the option to add rows/column like sales and expense report in the Reports tab.
You can check this link to learn more about Customise reports in QuickBooks Online.
Post again in the Community if you have more questions!