This isn’t dark matter, it is the normal matter which was supposed to be there but hadn’t been found before.
They're not the same, because the missing baryonic matter doesn't explain the observations that we attribute to dark matter. The missing baryonic matter problem is in addition to the dark matter problem. The most recent episode of Ask a Spaceman covers this, in case you're interested: https://www.pmsutter.com/shows/askaspaceman-archive/2020/5/2....