Dark matter isn’t matter, I know shitty name to call something “matter” that isn’t matter, Dark matter is a force. The most common example where dark matter shows up is in astronomy, where galaxy positions aren’t where we calculated them to be, hence there is some external force that is being applied, that we don’t know and haven’t found a way to take into account. I guess we call it “dark matter” instead of “dark force” is because for a force to be applied there must be some mass. Still i think it’s illogical to assume that dark matter is a matter, because we don’t know what force is exerting on it. For all we know it could be the accumulation of other galaxies applying a force on the observed galaxy that we’re simply not taking into account.