Applying for permanent residence permit

Germany is one of the rare countries that will sometimes tolerate a foreigner being granted residency as the parent of a local citizen child even though not married to a German citizen. But the conditions are strict. Usually the foreigner has to not only be paying for the child but living with the other parent; helping to raise the child and not just pay. But if they split up, one can always try. If one has a steady job, pays their taxes and obligations for child support, commits no crimes then they might be granted permission, but it's not guaranteed as far as I know. But I have to admit the details of such a scenario are beyond my knowledge.  I think what might seem to be a minor detail could be a factor, or sometimes it is really just a gray area at the discretion of the official deciding, and they might not like you. And work skills could come into play. If one only offers non-skilled or low skilled labor then they are seen as much less desirable as one offering highly demanded skills for which they might have a good chance at getting a job and work visa for in other contexts.