I have had a problem for a several versions of InDesign (using 16.1 right now).
When I start InDesign and want to create a new document with a shortcut Cmd + N shortcut I get an error beep and nothing happens. When I have a document already open this shortcut works as supposed?!
I have switched off the pontless blinking ADs called Home Screen and I use the Legacy New Dcument screen because I hate useless big icons that do nothing and I have to scroll for basic settings like Bleed and Slug.
I'm on InDesign 16.1, Mac OS 11.3.1 and have enabled the legacy New dialog box. Cmd+N works as expected with or without files open.
I would try rebuilding preferences.
No change in the InDesign behaviour after the Preferences reset. Still a beep on CMD + N and no New documet dialog.
I use it on two different machines -- iMac 27" and MBP 15", it is exactly same on both of them.
OSX is updated to 11.4 already on both.
How far down the post did you get? All the way to the bottom (removing/renaming ~/Library/Caches/com.adobe.indesign
and ~/Library/Preferences/Adobe InDesign? Those final steps tend to fix this sort of issues, but be sure to read the notes first.
If that's yes, then the next step is to report it as a bug, here: https://indesign.uservoice.com/.
Sorry to hear about your experience. In addition to the helpful suggestion given by Barb, I'd recommend trying the troubleshooting steps given on this community post(https://community.adobe.com/t5/indesign/resolve-slow-performance-and-unexpected-behavior-of-indesign.... Hope it helps.
I'd also recommend updating your app to the latest version of the app.