Be very careful about strenghting step links. One of their purposes is to bend rather than break something else.

If everything is working right a mast step should not bend. With everything working right, the main load is tension and some small bending.

A mast is a long lever. You can produce some big loads at the base. If something binds a flimsy step will bend. A solid plate will dent the mast or break something.

I am working on a step link for a Marstrom A. Since my history in structures has been kind of poor recently I borrowed a system to calculate loads for the CAD. My first cut was very solid and cool until the program indicated I might be able to break the base of my mast off. Since then sheet metal, bungee cords and nylon straps have looked pretty good.