iPhone 14 keeps freezing up

Hey there,

Try force restart your iPhone:

Press and quickly release the volume up button, press and quickly release the volume down button, then press and hold the side button. When the Apple logo appears, release the button, And Make sure that your iPhone is up to date ☞ Update your iPhone or iPad - Apple Support

if your iPhone is up to date or if you update it and you still facing this issue check this article ☞ About iOS or iPadOS performance on your iPhone, iPad, or iPod touch - Apple Support