iPhone 14 Pro doesn’t automatically switch 5G to 4G

Please read what is written in the pic below

Nowehere it says it will switch to 4G when 5G is weak.

In the areas where there is no 5G it will automatically switch to 4G if it does'nt that means there is no 4G even in that area. Contact your Carrier

Pardon my confusion. In your original post, you said the signal was weak, so I answered based on that information.

I believe this is something that is controlled by the carrier settings. You can check to see if yours need updating.

Manually update your carrier settings on your iPhone or iPad - Apple Support

Even though I have “5G Auto” enabled my phone doesn’t automatically switch to 4G when the 5G signal is weak. I’ve already tried resetting network settings

It probably won't switch automatically unless the 5G signal is lost completely.