Bigger phase detection points work better in low light. So for fast moving people in the dark, the later pro DSLRs work better.
For slow things, where you can wait for the camera to collect a lot of light the mirrorless cameras have advantages.
I was thinking about this comment last night and I've got to admit, in my opinion this is completely wrong.
Let's take the best DSLR available right now, which is the Nikon D850, it has AF sensitivity down to -4EV. It has 153 focus points, of which only 99 are cross type for increased accuracy.
The Canon R1 has AF sensitivity down to -7.5EV, this isn't 'close', it's almost twice as good, and it has 4,897 manually selectable focus points.
Even the Canon R3 which can be picked up for a decent price now has AF sensitivity down to -7.5EV, with 4,779 auto focus points.
My original R5 which I bought in 2019 has AF sensitivity down to -6EV, with 5,940 auto focus points.
So I'm really struggling to accept that any DSLR is better in low light conditions, even fast moving conditions.
"Mirrorless cameras use hybrid systems (phase and contrast detection) across the entire sensor, making them much faster at tracking subjects, including eye-detection, in low light compared to the limited, center-focused points of a DSLR"
I'm not saying DSLRs are no good, they're extremely capable cameras and I'm sure a lot of people use them with no issues, but you can't state the newer advanced tech in mirrorless bodies (and the AI available to manufacturers now gives them an insane advantage) is not better.
And on your final sentence, there is nothing slow about mirrorless bodies. So I'm not sure what or how you were testing.
