How can I disable Copy Paste shortcut on MacOS Sonoma while gaming?

While there isn't a direct way to do that in Settings, you can do the following:

1. Go to Settings > Keyboard > Keyboard Shortcuts > App Shortcuts (App Store icon)
2. Tap the plus button. Next to "Application", select the game name, next to "Menu Title" type a random text that doesn't correspond to any menu item in the application: it will trigger basically a nonexistent action, doing nothing. Finally, press ⌘+C after you click the box next to "Keyboard Shortcut"
3. Do the same for ⌘+V

Change a conflicting keyboard shortcut on Mac

It’s possible to have a keyboard shortcut that performs a different action depending on which app you’re using.

For example, Command-Space bar opens the Spotlight menu, but in another app it might do something else. You can change conflicting keyboard shortcuts so the same shortcut doesn’t perform different actions in different apps.

Note: Keyboard shortcuts in apps may vary depending on the language and keyboard layout you’re using on your Mac. If shortcuts don’t work as you expect, look in the app menus in the menu bar to see the correct shortcuts. You can also use the Keyboard Viewer to see your current keyboard layout, known as an input source.

Change a conflicting keyboard shortcut on Mac

1. On your Mac, choose Apple menu  > System settings, then click Keyboard  in the sidebar. (You may need to scroll down.)
2. Click Keyboard Shortcuts on the right, then in the list on the left, select a category, such as Mission Control or Spotlight.
3. A warning icon is shown next to conflicting keyboard shortcuts. Double-click the shortcut you want to change, then press the new key combination you want to use. See Customize keyboard shortcuts.

Look under Apple menu -> System Settings -> Keyboard -> Keyboard shortcuts