I'm on a very old OS version so i don't know what happened to it, but you can add any shortcut you want to any command you can find in the menu bar, for any app. Go to system preferences and in (iirc) accessibility somewhere in there is a place where you can add your own customized key commands.
Apple
Here you can talk about Apple's ecosystem, Apple's OSs (Operating Systems), Apple's apps, Apple's everything!!
Yeh I found someone's stack exchange post with that very idea. I've gone ahead and done that but the result is weird. Like that person, despite the command being explicitly set as cmd+return, it has somehow been changed to cmd+shift+return, something I was only aware of because of that guy complaining about it. but worse still, on some obscure occasions, the app will refuse to do even that, and in fact on those occasions, refuse to accept even it's official command of cmd+shift+D. I could no figure out what Mail's problem was on those occasions, getting only a warning chime but not explanation. I assumed there was something wrong in the sender field, but clicking the send icon worked fine so it's just WTF? Oh well, I'm content with cmd+shift+enter for those occasions when Mail feels like it. Can't do much about when it doesn't.
This is the shortcut for Outlook and Thunderbird, could it have been you were using a different mail client before?
I don’t like it either but I just remember D for despatch.
What I struggle with is the inconsistency in Zoom shortcuts in Apple apps.