I think JJ has far more impact on games than Mount, he just needs to do it more often.
Mount is an international because he's one of the media darlings of Southgate. I doubt many other managers would be picking him given the riches England has in his position.
Top 4 quality? Chelsea finished 11th didn't they? CL level? Depends on your criteria. Lots of mediocre players have CL experience.
It's all about opinions, and to me, Mount isn't in the top 10 Englishmen in CM.