Hardox or simular kinds of steel are an affordable option. Cheaper than the less suitable stainless, and way stronger than mild steel.

But with spinner power as it is now, we're looking at 8mm+ of hardox 500 or better.
And that with as little welds as possible, all angled to deflect hits.

The other option is to use titanium , grade 5, and that is costly, with a pricetag 15 times higher per kilo than hardox.... For only a 33% weight benefit for the same thickness.