You can easily bulk-edit all rdp connections even from different folders. you simply enable the option to show all objects from the subfolders in the dashboard and sort/filter by remote desktop connection type. you can then simply select all your connections in the doc.
As far as I know, zoom only works if the remote OS implements the necessary APIs. Not all Windows versions support DPI zoom. So the issue with Hyper-V is that you are essentially connect to a “virtual console” session which isn’t aware of any OS beneath. I’m afraid there’s nothing on our side we can do to make that work. MS needs to implement “zoom” support when connecting to a hyper-V host’s console session.
DPI awareness has it’s limitation because MS didn’t really implemented it fully. See also: Run Royal TS on High DPI Displays
If DPI awareness limitations are a showstopper for you, I recommend to uncheck “Disable display scaling on high DPI settings”. In this mode, the OS fakes a 96DPI system for the window and scales the window as it were a non high DPI process. The result is blurry icons but the sessions should be scaled correctly in any situation.