So Absalom Station is supposed to be 5 miles in diameter and house 2 million people? Is this a typo or something cause that's physically impossible. Mechanically medium creatures seem to be a 5'by5'by5' cube, so without squeezing the majority of Absalom Station's citizens take up said space.
Now going back to the 5 mile diameter; Absalom Station is supposed to be a dome. This means that the volume of Absalom Station, i.e. total space within it, is equal to half the volume of of of a sphere of equal diameter. Therefore, the volume of Absalom Station is equal (4*pi*2.5^3)/6, or 32.725 miles cubed. Now since there are 5280 feet in a mile, multiplying the cubic miles by 5280 will give us the cubic feet of 172,788.
Returning to my previous point about the space most citizens take up without squeezing; this is 172,788 ft^3 that can be divided amongst the citizens and visitors of Absalom. So, since the most citizens are medium, we can simply divide the cubic feet by 5 to determine the MAXIMUM number of medium creatures that can be in Absalom Station: 34,557.
This is assuming that there's next to nothing except people in Absalom Station. At most this could also include walkways to account for the part where this number has people onto of people. However there would always be someone next to someone else, privacy wouldn't actually exist, etc.
So will this be corrected at any point? Cause the inaccurate world building is really kinda irritating. I'll even make it easy for y'all! 2 million people in the station? So that's 2 million 5'by5'by5' cubes to make math simple. multiple by 5 for cubic feet, that's 10 million cubic feet. Then you divide by 5280 for the cubic miles, 1893.9;round down to 1893. That's the MINIMUM possible volume. Now multiple by 6 and divide by 4*pi for the radius cubed, 903.8; round down to 903. The cubic root of 903 is 9.66 so the diameter of Absalom Station had to be at least 20 miles for it to CONTAIN 2 million medium creatures.
Let's add infrastructure, privacy, space for visitors, businesses, etc. Let's be really really conservative and only triple the space we want. 5679 cubic miles, so a diameter of at least 28 miles. And honestly, I'm probably massively underestimating how much more space you'd need.