Phone freezing during calls and when I highlight a word to change it

Hello. I have an iPhone 12 Pro max. When I am sending a text message and see a word I need to change, prior to Saturday, I was able to double-click the word, highlight it, and retype a new word. Now, I try to do that, and the whole text freezes. When I close the app and reopen it, everything I type is gone.

Additionally, randomly, when I am on a call (this started Sunday), my whole phone freezes. I can not hang up, restart it, or receive incoming calls. I have never had this kind of iPhone issue, and I am becoming vexted. If I am in an emergency situation and it freezes, I can not call for help.

How can I fix these issues before I go crazy?