Hello,
Thank you for posting in the Microsoft community forum.
I understand that your remote desktop client is not working properly after updating the MacOS system. Please check that all available patches in the system update are installed.
This seems to be a known issue related to MacOS 15 Sequoia. You are advised to check for Remote Desktop client version updates or download the latest version of Microsoft Remote Desktop client from the Mac App Store.
If the problem persists, we sincerely hope that you can help us improve your Windows experience by reporting this phenomenon through the Feedback Center app and sending us your suggestions:
Send feedback to Microsoft with the Feedback Hub app - Microsoft Support
Reference:
MacOS 15 Sequoia upgrade - Microsoft Remo… - Apple Community
I hope this helps.
Best regards
Jacen