Microsoft Remote Desktop client for Mac has a long and ghastly history. (Yes ghastly is the right word and this is not a typo where 'glorious' should have been used.)
Version 1.x had a bug whereby anybody using a Mac with a non-US keyboard was tortured by the software failure to map keys correctly to the Windows session. The most infamous examples of this where that the Mac " (speech marks) key would generate an @ (at symbol) in Windows and vice versa although a number of other incorrect key mappings also apply.
Version 2.x did finally fix this bug.
Microsoft then bought a 3rd party RDC client and this became the next Microsoft official client and I cannot remember if this was released as version 5.x or 7.x. Regardless as this was new/different code it REINTRODUCED THE SAME BUG!!!
Note: I have just reproduced this with Microsoft Remote Desktop 10.8.1 (2048) running under macOS Ventura 13.2.1 with as mentioned a UK Mac keyboard.
Literally thousands and thousands of Mac users throughout the world except the USA have been complaining about this ever since.
When I last was personally victimised by Microsoft with this issue many years ago I also reported this but I found that the Parallels Remote Desktop Client for Mac did not have this bug. The reason being it was not written by American programmers who are wilfully ignorant regarding international keyboard layouts.
Unfortunately I now once more have to use an RDC client and I am finding that the Parallels client whilst still available is not connecting to the Microsoft RDC server whereas the Microsoft client does successfully connect even if it then inflicts cruel and unusual punishment in the form of this now ancient keyboard mapping error.
I have however been able to prove that the RDC client for Mac available here - www.jumpdesktop.com DOES connect to the same Microsoft RDC server and DOES NOT have this keyboard mapping bug. However the JumpDesktop client is a chargeable product.
Microsoft over the decades has in a number of cases committed grave offences against Mac-kind but in more recent times has been comparatively friendly to the Mac using community. Why therefore is this bug which affects potentially BILLIONS of people around the world i.e. anyone who does not have a Mac with an American keyboard still not been fixed?
PLEASE FIX IT AT LONG LAST!
How to reproduce.
1. Connect a non-US keyboard to a Mac, this could be a USB or Bluetooth keyboard, it does not have to be an Apple brand keyboard but genuine Apple keyboards would be the most common use.
2. The Mac should be configured to use the relevant keyboard layout - in my case this is UK but I know that it affects all other non-US layouts e.g. French, German, etc.
3. Connect to a Windows RDC session
4. On the Windows desktop open an app like Wordpad
5. On the Mac type in to the Wordpad document abcdefghijklmnopqrstuvwxyz these all map correctly. Now on the Mac type the @ (at) symbol, in Window you will instead see the " (speech marks) symbol, now on the Mac type the " (speech marks) symbol, in Windows an @ (at) symbol will appear. As mentioned other keys like the \ (back slash) are also incorrectly mapped.
6. Download the trial version of the JumpDesktop client
7. Use JumpDesktop to connect to the SAME Windows RDC server
8. Repeat the same typing test in to Wordpad, this time all the keys are correctly mapped with no settings having to be altered either on the Mac or in Windows.
Conclusion, Microsoft programmers are at fault.