I always hear this argument that the employer controls your health care in the U.S. and it is quite wrong. The employer MAY offer one or more options for a subsidized health care plan in which the employer contributes some or all of the cost of the selected plan. There is zero requirement for an employee to select or use such a plan, and there is absolutely nothing stopping an employee from seeking an alternative plan or additional uncovered treatments through other means available to them.

Maybe there is a point to be made about the overall cost of health care plans being too expensive for an individual to afford without the employer subsidy, but that is orthogonal to "employer control" of healthcare.