While it’s true that the U.S. spends way too much on healthcare (more than any other country as you said), the fact that it has a mediocre life expectancy is almost entirely due to things that have little to do with the quality of health care. Much more driving than most other countries resulting in more auto accidents and thus deaths, way more guns resulting in more murders and suicides, etc. Drug overdoses, in particular opiates, are probably the biggest one than can arguably be linked to healthcare.