Microsoft RDP for Mac problem with iPad and Sidecar

Hello,

I use Microsoft RDP for Mac to connect to a Windows computer, I have a primary 4K screen and an iPad a secondary display (configured with Apple Sidecar). When I check the "Optimize for Restina Display", the RDP screen is black on the iPad but on the primary display, It works fine. When I uncheck the "Optimize for Restina Display"  option, the iPad shows the screen like the primary Display. But the primary display is blurred ... It's normal, It is not retina ...

The iPad Air 4 is updated to the last version of iOS, the Mac is on version 12.2 and Microsoft RDP app to the last version too.

Thanks for your help.