Would like to get one management report with both balance sheet and profit and loss like a typical financial statement.

Do you need to consolidate reports from 2 QBO accounts? You can use a BI app to generate them. 

Hi there, Yaakov. I'll help you get one statement from two reports.

In QuickBooks Online, getting one statement from two financial reports is impossible, but we can export the report to Excel and combine them. We can also utilize the third-party app, just like what Chrea mentioned. Here's how to export:

1. Go to Reports.
2. Select the report you want to export. 
3. Click the Export/Print dropdown
4. Hit Export to Excel and save the file where you can easily find it.

Please note that if your file is protected, you must select Enable Editing to view the report. To help you customize your reports, check out this article: Customize reports in QuickBooks Online using modern view.

I'll be here if you still have questions about your reports. Have a great day, and take care.