Fortnite swastika creative?

Is it punishable or can I be banned if I build a swastika in Fortnite creative mode?

No matter where, no matter when. I don't know where you live, but in German-speaking countries it is painting / building / drawing / etc. A swastika punishable.
If someone catches you, no, actually he has to report you.

Even if you go in on the grounds that it's just for fun. Does not matter. Does not count as a valid statement.

If you can't hold on, do it. But after that, be sure to delete the map again. And it's best not to do it again.