Why is my predictive text feature grayed out on iPhone?

When I go to keyboard settings the predictive text settings is turned off or grayed out and now Apple wants me to use ChatGPT which I tend to find unpredictable when trying to use. I have difficulty spelling with Asperger’s spelling and find the dictionary is far more precise. How do I turn it back to the original settings?

[Re-Titled by Moderator]