I think you are out of luck, I don;t think you can download it from anywhere else.
Apr 01, 2020. Download this app from Microsoft Store for Windows 10, Windows 8.1, Windows 10 Mobile, Windows Phone 8.1, Windows 10 Team (Surface Hub), HoloLens. See screenshots, read the latest customer reviews, and compare ratings for Microsoft Remote Desktop.
Maybe also look into http://cord.sourceforge.net
Why don't you try downloading it on your computer and see if you can extract the file from the download? Right-click and show package content.
PS: Is that: https://www.microsoft.com/en-us/download/details.aspx?id=465 the right client?
I can't test it since I don't have a MAC at work.
Rdp Client For Mac Download
or this one: https://www.microsoft.com/en-us/download/details.aspx?id=18140