Thinking out aloud here, if you had a short rope with a handle on the end fixed on a wall at your shoulder height and you had a board on wheels against the wall that you could stand on. You could put on a glove hold the handle and slowly you could mimic the punch evn with twist and slowly push yourself off the wall and then drag your own weight back to the wall so you could start again. Add weight or damper down a wheel.

Would that kind of thing be a help? You would be off your heel in a real stance that wasnt fixed into a position and you'd be working both sides of the muscles from the toe up to the neck and through the real motions used but with resistance. If you did it on a pole and had a trolley that had directional wheels you maybe able to incorporate hooks too.

Thoughts