I assume in saying a TM4 iron you are referring to a TaylorMade M4?
That is a very strongly lofted iron. So if you are using a 6 iron for your 150 shot I really don’t think the ability to shape a shot is your issue or what may be holding you back. Lack of club head speed probably has you struggling with ball flight being too low. Your goal should be to simply hit a straighter ball. This is purely my educated guess as not seeing you play leaves out a lot of details.
Rather than attempting to shape a shot with equipment changes I would see a teaching Profesional and get a game plan for better golf through a few lessons. With that have him evaluate your equipment and go from there. Chasing better golf can send you down a rabbit hole without a good plan.