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2) the Bullet cluster is a more complicated structure than a binary system of two big dark-matter clumps that are offset to the baryons:
arxiv.org/abs/2503.21870
Masses were reduced and bounds on SIDM were set. Looks like we need less dark matter if the structure is more complex!

...and there is also a method to constrain dark matter properties purely from the multiple images, see this NASA press release for more:
https://science.nasa.gov/missions/hubble/double-galaxy-mystifies-hubble-astronomers/