Hands in both photos are incorrect.
And I imagine problem could be solved, if you are using curb chain, by loosening it.
If not using curb chain, which you should be on a shanked bit, I would say your hands are too heavy, not soft enough.
Horse is not getting any release when tucks head, so keeps tucking more and more trying to get relief.
How are you holding your hands, how responsive is horse to your cues, and what type of curb chain are you using?
And where did you get picture of man plow reining in a show ring????
Horses make me a better person.