The F-35 is an expensive platform with which to replace the entire inventory of AF, Navy and Marine fighter and attack aircraft.
But …
For it’s air superiority mission, it is awesome. It gives the President a tremendous option in considering threats as they arise.
Without identifying the country, let’s say the Organization of American States authorizes the use of force to restore democracy to a particular country in this hemisphere, equipped with Russian military equipment.
With a squadron of F-35s, the President could be pretty confident of controlling the airspace over this unnamed country. In the meanwhile, F/A-18s - more robust in terms of munitions packages and time over target - made sure that tanks and other armored vehicles remained in place.
“For it’s air superiority mission, it is awesome”
The F-35 isn’t an air superiority fighter. The role you describe is the job of the F-22.