Why are attachments in Outlook not opening to my default/desktop app, only as a preview in Outlook, when updated to Windows 11?

I have a few users who recently switched to Windows 11 asking why attachments from outlook won't open on their desktop apps, only as a file preview in Outlook. My users are trying to move through a lot of communications at once, so needing to manually save and reopen the files on their desktop apps is clunky and adding inefficiency their work. The files they need to open also need to be manipulated, so leaving them in Outlook preview won't cut it (approvals, highlights, etc.). Short of reverting my users back to Windows 10, I have not found any other question thread or app setting that works to adjust this.

On Windows 10, double left-clicking an attachment in Outlook pops the "Opening Mail Attachment" window then allows me to open in my default viewer (e.g. a .pdf file will open in Adobe on click for me); in Windows 11, "open" and "always ask before opening this type of file" not selectable (grayed out). I can "save" the documents to my desktop then open them in the default viewer in Windows 11, but not open on click as before. Sorry for not having screen shots - pictures were not loading.

To my knowledge, here were no changes besides updating to Windows 11 (no policy change, no settings change, trust center is the same, etc.).

Outlooks performance with attachments on Windows 10 is much more intuitive and useful to us. What do I need to change to allow users updating to Windows 11 the same performance, or what could be causing this feature of Outlook to not work the same on Windows 11?