Italian keyboard doesn't follow shortening

it’s since a have iPhones that I try to teach the Italian keyboard do’s and don’ts. Without success. I use shortenings in the keyboard section in settings (text replacement: sostituzione testo in Italia, no idea of how it is called in English). Examples:

1) when I write E the keyboard must leave E. But it always changes with È. Even if I correct immediately, it changes it again and again!

2) same as before but with “CE” and “C’È”.

If there are rules I gave, why in the name of god the keyboard does whatever it wants?

This must be fixed once and for all!

The English keyboard is perfect: why the Italian one gives us all this issues?