I've been trying (with mediocre results) to use the Autocorrect feature to automatically italicise words in a way that is font (and size) agnostic. In other words, I only want the Autocorrect to italicise a word, not to change font or size. I am scrupulously following these instructions:

1. Type the word I want to italicise;
2. Select the whole word;
3. Press CTRL + I to italicise;
4. Open the Autocorrect Options window (ALT + T, then A);
5. The selected word usually appears in the "replace" box;
6. Click on the "Formatted text" radio button;
7. Click OK.

This procedure only works at random, meaning that sometimes it works, sometimes it does not, and I really can't understand what I'm doing wrong. Most of the times, when I type the word (after having followed this algorithm), not only it gets italicised, but Word also changes the font and the size to match the ones I was using when I called the Autocorrect Options menu. Only on rare occasions the word gets memorised correctly, that is to say, when it is typed it is automatically italicised (and only italicised).

P. S.
I'm using Microsoft 365 under Windows 10.