Eno

It's a very long time since I've restored from a Time Machine backup but there's no harm in following that route. If you don't like where it takes you don't do anything! However, I think you'll find it should work. It may try to restore the file to the original location—which may or may not work with the upgraded OS. However, I think you can simply copy the file (once you've found it) and then paste it to your desktop if you want to take it in stages.
 
Stephen

Assuming you know how to recover a file from a Time Machine backup you'll need to be looking for your Alfred preferences file which you'll probably find in ~/Library/Application\ Support/Alfred/. (I'm assuming you were not synchronising your preferences between Macs previously.) You need to recover that old file and (after quitting Alfred) put it in place of the existing one on your new Mac (which will obviously overwrite any existing preferences and workflows on your new Mac, so be careful!).
 
Stephen

Got it working by deleting the corrupt file. Thanks for your assistance.

Welcome @Eno,
 
⌘, isn’t a global shortcut, but a common way to show the preferences in most macOS apps. To open Alfred’s Preferences with the shortcut, you need to have Alfred’s window as the frontmost window before pressing it. Alternatively, you can invoke Alfred and type preferences.

If that is what you’re doing and it still doesn’t work, can you post a video? You can record your screen with QuickTime Player.