Press and hold the Side button and either Volume button until the power slider appears
Drag the slider to turn off the iPhone
Wait a few seconds
Press and hold the Side button again until the Apple logo appears
If the phone is frozen, quickly press and release Volume Up
Quickly press and release Volume Down
Press and hold the Side button until the Apple logo appears
If SOS appears, release the buttons and try again with the correct button sequence
If needed, remove the case so the buttons can be pressed properly