How to disable Apple Intelligence in Mail?

Something that REALLY annoys me is that sometimes when I start a new message in Mail and tab to the text area a popup box appears with AI suggestions for text. If for example I type "Dear XXX," then hit return to go to the next line it ignores my return and carries on along the same line until I look at the screen and hit the escape key to get rid of the popup box.

I have looked into how to disable this and it seems that the only way to do so is to completely disable Apple Intelligence altogether - you don't seem to be able to selectively disable this aberrant behaviour in Apple Mail.

Any thoughts on this?