Can I turn off the Emoji & Symbols keyboard shortcut?

Applications that offer the Emoji & Symbols Edit menu item "listen" for that keystroke as it is a compile time menu item and cannot be changed or disabled.

Each Emoji & Symbols panel is an originating application focused entity and when you launch or switch to another application, focus is lost on the associated Emoji & Symbol panel and it is unmapped from view. When you switch pointer focus back to the previous application, the Emoji & Symbols panel is exposed again for that application until you dismiss it.

You can reduce the reliance on the Emoji & Symbol panel by taking advantage of frequently used symbols that you assign as text replacement items in the Keyboard Preference panel. As long as the application you are in offers an Edit menu : Substitutions : ✓ Text Replacement feature, when you type the trigger characters, a pop-up will appear allowing you to insert the character or character sequence you have constructed, or that you choose to dismiss with the ESC key.

Here is an example of some of mine where is create the Replace trigger characters and use the Emoji & Symbols panel to insert the With string:

tavao wrote:

Would creating a different shortcut turn off control + command + space?

On my Ventura, I changed that shortcut to Command 6, and that now brings up Character Viewer and Control Command Space does nothing.