Where it's reported is correct (schedule 1 line 16). you do not reduce self-employment/schedule C income for profit-sharing contributions made for yourself. the line for pension and profit sharing on schedule C is for contributions for employees. you are not an employee.
an alternative might be to elect S-Corp status - you would be an employee but would also need to take a salary. there are many other pros and cons to doing this. so consult a tax pro.
