Hi AH21,
The profit and Loss report only shows all income and expense accounts used on a transaction at a specific time. If you have made payroll payments, the payroll journals exported to QuickBooks Online are based on the default chart of the account you've set up like the Wage/Payroll expenses account. Usually, that's the expense account shown in the Profit and Loss associated with any payroll payments made.
If you've paid payroll payments using the projects feature, it's best to run the Project Profitability report in the Projects tab. Another report you can run for payroll payments is your Detailed Activity report in the Reports tab.
You can check this article to learn more about Track hourly labour costs and profitability by project in QuickBooks Online.
Post again in the Community if you have more questions about QuickBooks Online!