If I choose, for example, File/Open or File/Save As, I can type text into the Search box in the Dialog that appears.
That’s not the case for File/Import/Research Files as Aliases … If I try to do that, I get the error boop.
Why it’s important: I have over 500 images in my BookImages folder, so it’s inconvenient to scroll through the list to find the one I want to open.
This isn’t happening for me. Since you seem to experiencing general focus/typing/beeping issues, it might be worth logging out and back into your account with the Shift key held down. Just press it the moment you enter your password, and keep it held down until log in is complete. That’ll keep all background utilities and such from running, so no macros, cloud, etc. If these issues go away, then you’ll just have to narrow down which background utility is interfering with input.
Got it. I’ll work on it.