Hello there, Mdawini_23.
Let me share information on how Spreadsheet Sync works in QuickBooks Online Advanced.
The Spreadsheet Sync has a standard report for Profit and Loss that's why you're unable to generate it by month or by customer. Also, increasing the report options while using the spreadsheet sync feature isn't possible since it has Simple Management Report with formatted/standard spreadsheets, such as Trail Balance, Balance Sheet, and P&L.
To know more about using Spreadsheet Sync, see these articles:
If you have further questions about using Spreadsheet Sync, let me know by commenting below. I'm here to answer them for you. Have a great day!