Heavy gauge expanded mesh steel grating is what I would use. Great traction and durable. Snow, mud, and ice loading can be easily mitigated with a blower as it starts to build up. I would think any steel supplier by you can cut it to order. Attaching it to wood use heavy fender washer and a thru...
It certainly looks like a “couple hundred bucks” fix not repair. It looks like there is undercut, porosity, inconsistent bead profile, and poor blending, all the ear marks of future failure. Just saying but I wouldn’t be happy with that, at all.