From Frank C:
Print it, bookmark it, memorize it: Here is every shortcut you need to master your Mac.
https://www.macworld.com/article/3144751/macos-cheat-sheet-mac-keyboard-shortcuts.html
Keyboard Shortcuts to Interact with Siri AI
from John C:
You can use keyboard shortcuts to interact with Siri AI on your Apple devices. On macOS, you can set a custom shortcut to activate Siri by navigating to System Settings > Apple Intelligence & Siri > Siri Requests > Keyboard Shortcut. The default shortcut is to press either Command Key twice.
On iOS and iPadOS, you can assign keyboard shortcuts to specific Siri Shortcuts by enabling Full Keyboard Access in Settings > Accessibility > Keyboards > Full Keyboard Access, then customizing commands to run your desired shortcuts.
NOTE: Enabling "Full Keyboard Access" on an iPad with a non-Apple keyboard case will change how the keyboard behaves. I haven’t confirmed if it changes the external keyboard on an Apple keyboard case, but I’m definitely not happy with how it changes the way the keyboard behaves on my non-Apple keyboard case. It may be best to just put the Siri app icon on the Home Screen.