TPS548A28: DCAP3 DC gain

Table 7-2 has the zero locations https://www.ti.com/lit/ds/symlink/tps548a28.pdf#page=18

The small single model can be better understood running an AC simulation using the Simplis model on product folder

https://www.ti.com/product/TPS548A28?keyMatch=TPS548A28&tisearch=search-everything&usecase=GPN

Figure 8-34 on page 37 of datasheet shows the Bode plot,  the gain can be derived from the plot.  Vout=2.5V and Vref=0.6V.   https://www.ti.com/lit/ds/symlink/tps548a28.pdf#page=37

 The wri zero in the figure 2-3 graph is the Tc in equation 1 and is higher than LC double pole.   

  The TPS548A28 zero locations for TC are in the table 7-2.   

I believe the low frequency pole and zero you are highlighting  should be not be a concern when following the design procedure outlined in the datasheet or the webench design. 

There is a circuit in the feedback path that minimizes the dc error and shows up in the low frequency ac response.   I will contact the SLVAF11 app note authors to see if the have add any details on the low frequency response.