Thanks for looping in, @4G Expo.
Adding the accumulated billable hours of an employee to their paycheck without being counted to the total payroll is currently unavailable in QuickBooks Online. For now, I recommend performing the solution you find as a temporary workaround.
Rest assured, I'm passing this idea to the appropriate department for consideration in future product enhancements.
In the meantime, I also suggest visiting our QuickBooks Online Blog to get recent news and feature updates. I’ll let you know if there are any changes by updating this thread.
I’m always here to help if you have additional concerns. Wishing you the best!