Six months into the role, Homeland Security Secretary Markwayne Mullin has “struggled to overcome doubts” among both MAGA influencers and the White House, The New York Times reported Sunday, particularly with his efforts to “prove his toughness.”Mullin replaced Kristi Noem as Homeland Security secretary in March, and in the months since, has repeatedly touted his efforts to ramp up deportations of undocumented migrants.“Next stop Ecuador,” Mulli…