Hi, and yes, it is possible to use multiple monitors with Microsoft 365 Virtual Desktop.
https://techcommunity.microsoft.com/t5/windows-365/windows-365-and-multiple-monitors/m-p/3068863
Try next:
Open the Microsoft Remote Desktop Client Application.
Right-click on the Cloud PC icon and select Settings.
Toggle the “Use default settings” button to the OFF position.
From Display Settings, you may select your desired display settings from the display configuration dropdown (Select Displays/All Displays/Single Display).
Please note that you should be using the 64-bit version of the Microsoft Remote Desktop Client, as recommended on the Windows 365 client webpage.
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I hope this helps! If you have any more questions or need further clarification, feel free to ask. I’m here to help!