In general countries have jurisdiction over anyone inside their territory unless there is some exception.

As far as I know the only exceptions at the time the 14th was drafted and ratified would have been people with diplomatic immunity or similar due to treaties and international agreements.

Immediate families of diplomats living with the diplomat are included in diplomatic immunity, hence their children born here would not become citizens.

Those situations you mention where US court do have jurisdiction over diplomats are: private real estate disputes; wills and inheritance; business activity of diplomats that are running a side business or practicing a profession in the US that is not part of their official duties; lawsuits initiated by the diplomat.

Even if becoming subject to such limited jurisdiction counted as being "subject to the jurisdiction" for purposes of the 14th Amendment it would not matter because newborns are not involved in those things, and so newborn children of diplomats have their full diplomatic immunity.