Apply for PhD before finishing my Master's degree

It's not a big deal for you not to have publications—remember, many of your peers also will not have published anything, either!

Moreover, it's important to note that in the US, most of the applicants for graduate school do so in the fall of their fourth year of studies—which would, contentwise, typically line up with the third year (or sometimes even second year!) of study in a German program. So, in many ways, you're already much more experienced than your counterparts.

If you're interested in doing this, I would recommend that you just go ahead and apply. The worst that can possibly happen is that you're not accepted, in which case you find another means of achieving your goals.