I don't think cast iron is really any better for induction than carbon steel, at least in my experience. You're right that it's basically impossible to season either properly on an induction hob, and you'll get the same uneven heat distribution with cast iron - maybe it's just not a problem when you're using the wok.Problem I have is I just cannot get a good season on the one I have.
It's a De Buyer mineral b, so should be a good pan but whatever I do it'll stick then char on crust.
I even completely stripped it, tried building up so very thin/light season layers but soon as I tried to use it, nope. Tried every YouTube method, everything.
I reckon it's how my induction hob transfers the heat through the pan, because you got like a hot ring in the middle then cooler around the edges.
I have a carbon steel wok, and that one is fine, although that one I only use on an outdoor gas burner, so maybe it is my hob. I also have a cast iron wok and the thing is just so easy to maintain, I even occasionally wash it in hot soapy water, and after re-season it's good to go, and that is on the induction. But it's put me off trying another carbon steel.
I think cast iron is a lot more forgiving, maybe better for induction.
Have you tried seasoning the De Buyer pan on your outdoor burner? I have one of those pans, and once I got a gas burner I was able to get a decent seasoning on it.