Somewhat common issue of "flatten then fling" ... aka 'bat drag'.
Example .....
How do you fix it? I've seen this in her swing... but I'm not sure the drills to use to fix it.
Review the clip below. Notice that at the pause that the palm of the top hand (right hand) is orientated towards the sky. Give your daughter the goal of having the palm of the top hand orientated such that it points back more towards the pitcher than towards the sky.
The palm of the top hand may end up orientated towards left-field ... that's a good thing.
This may be one of the most useful things you posted on this subject, FFS. Good input.