Disable Apple Intelligence

Although Apple Intelligence offers a number of interesting capabilities, they are not useful to everyone. They use up computer resources and sometimes provide annoying suggestions and feedback. Sometimes they are faulty.
Removing Apple Intelligence is easy. Go to System Preferences and select "Apple Intelligence & Siri" and deselect Apple Intelligence (red arrow).

Remove AI from a Mac

Remove AI from an iPad
The iPhone is the same.
Apple Intelligence can be turned on at any time by reselecting it. It takes several minutes to reload.