Hi Rich Simpson,
Welcome to the Microsoft Q&A Platform! Thank you for asking your question here.
Microsoft is transitioning from the Microsoft Remote Desktop app and introducing a new Windows App, starting in September 2024. This change has led to some confusion, as the older app has been removed from the Mac App Store, and now links redirect to the Windows App (currently in preview for macOS). For users on macOS, iOS, and Android, the Windows App will completely replace the previous Remote Desktop Connection app—an update to the Remote Desktop app will automatically switch it over to the new Windows App.
For more information, please refer to https://techcommunity.microsoft.com/t5/windows-it-pro-blog/windows-app-now-available-on-all-major-platforms/ba-p/4246939
If you have any further queries, please do let us know.
If the answer is helpful, please click "Accept Answer" and "Upvote it."