The original article (Reconstructing
biblical military campaigns using geomagnetic field data) in the October 24, 2022 issue of Proceedings of the National Academy of Sciences can be read here.
Explaining the method used it says:
The Hebrew Bible and other ancient Near Eastern texts describe Egyptian,
Aramean, Assyrian, and Babylonian military campaigns to the Southern
Levant during the 10th to sixth centuries BCE. Indeed, many destruction
layers dated to this period have been unearthed in archaeological
excavations. Several of these layers are securely linked to specific
campaigns and are widely accepted as chronological anchors. However, the
dating of many other destruction layers is often debated, challenging
the ability to accurately reconstruct the different military campaigns
and raising questions regarding the historicity of the biblical
narrative.
The destruction of Jerusalem as one of those chronological anchors is based on an earlier article (The Earth's magnetic field in Jerusalem during the
Babylonian destruction: A unique reference for field behavior and an anchor for
archaeomagnetic dating) in the August 7, 2020 issue of PLoS One (PLoS = Public Library of Science) journal, which can be accessed here.
In that article it says :
Unlike biblical sources regarding earlier periods, the detailed biblical
descriptions regarding the end of the Iron Age and specifically the
destruction of Jerusalem by the Babylonians in 586 BCE are considered
historically reliable by the vast majority of researchers.
In support it cites The fall and rise of Jerusalem: Judah under Babylonian rule (2005) by Oded Lipschits and two articles in the journal Zeitschrift des Deutschen
Palästina-Vereins.
So the date of 586 BCE for the destruction of Jerusalem is not based on archaeomagnetic dating, but it is used as an anchor because it is considered historically reliable. The
diagram below of field intensity results does help to give an idea of sequence but the dating is based on the anchors.

Yes, I know that's what slim said yesterday, far more succinctly than I have done, but I thought it would be of interest to read the original articles.