Sure, you can make whatever you want from the original designs (but note not from any elements from figurines or films or anything else DC made that deviate from the comics).
However, that in and of itself isn't depriving DC of anything, as they're no worse off financially than if whatever you make never existed. Arguably, if you create something that's a runaway financial success, and someone has to choose between buying your thing and the DC produced thing, then sure maybe then DC loses a sale. But sales are rarely binary like that. If you do something that promotes the brand, it probably benefits DC's sales as well.
The only thing that might actually impact on their profit is someone producing an exact copy of the original comics, at a lower price, and of better quality. Even then, people might still buy the DC version so it matches the rest of their collection. And if it is an exact, exact copy of the original comic, there's always a risk there might be something with a DC copyright on it, e.g. the font that's used in the title, maybe a reference to some other DC property, etc...
However, that in and of itself isn't depriving DC of anything, as they're no worse off financially than if whatever you make never existed. Arguably, if you create something that's a runaway financial success, and someone has to choose between buying your thing and the DC produced thing, then sure maybe then DC loses a sale. But sales are rarely binary like that. If you do something that promotes the brand, it probably benefits DC's sales as well.
The only thing that might actually impact on their profit is someone producing an exact copy of the original comics, at a lower price, and of better quality. Even then, people might still buy the DC version so it matches the rest of their collection. And if it is an exact, exact copy of the original comic, there's always a risk there might be something with a DC copyright on it, e.g. the font that's used in the title, maybe a reference to some other DC property, etc...