Keyboard shortcut for Launchpad doesn't work

I can start Launchpad using a gesture on the trackpad, by searching for the app in Spotlight, or by double-clicking in the /Applications folder, but I can't launch it from the keyboard. I have created a keyboard shortcut (System Preferences > Keyboard > Keyboard Shortcuts... > Launchpad & Dock > Show Launchpad), but it does nothing when I use it from my account. It works fine if I log in using a different local account on the same machine, so it is something specific with my configuration. It doesn't matter what key combination I choose. The same key combination works fine when assigned to other actions, so I don't think it is another app trapping the keyboard shortcut. I've tried resetting the Launchpad db (using TinkerToolSystem's Reset Launchpad to Factory Settings). This reordered the icons (as expected), but didn't fix the keyboard shortcut. I've tried a few command line suggestions (e.g. defaults write com.apple.dock ResetLaunchPad -bool true; killall Dock) as well as other suggestions, but they mostly seem to be trying to do what TinkerToolSystem did. I am using macOS 15.3.2 (Sequoia) and I just rebuilt the system from scratch. I had the same problem intermittently on earlier versions of macOS too though. I have no idea what to try next. The closest I could find online is: https://apple.stackexchange.com/questions/437722/how-to-reset-launchpad-shortcut-after-it-stopped-working The suggestion did not work for me.