Open Settings
Tap Accessibility
Tap Side Button or Home Button
Under Press and Hold to Speak, select Siri or Off
Go back to Accessibility
Tap Voice Control
Turn off Voice Control
If Voice Control is enabled by Siri, say “Turn off Voice Control”
If Voice Control keeps turning on, check Accessibility Shortcut
Go to Settings
Tap Accessibility
Tap Accessibility Shortcut
Deselect Voice Control
Restart the iPhone if needed