How do I disable RTT/TTY call function on iPhone 16 for hands-free driving?

somehow I set up the option of RTT/TTY calls (can text to the person you are talking to and phone will read the text instead of you talking?) and it makes it impossible for me to have my car Siri make a call as I have to choose which method I want ( which I don’t want to have to do while driving). Can someone PLEASE guide me as to how to get rid of that function?

THANK YOU!

[Re-Titled by Moderator]