The XSX's design is much like Apple's 2013 Mac Pro in its cooling solution. Eg the "Chimney" airflow cooling approach.
There have been PC cases with a similar design though, eg the OSMI mini ITX PC case, which uses the same principle of sucking in air from the bottom (and side), but also pushing air out through the top, but obviously it has to use off the shelf parts and hence has greater airflow limitations.
In that sense the XSX's take is considerably more elegant and efficient than the OSMI's, and would probably get far better cooling results.
Tbh, using the DS4 as the go to comparative is not a good idea, because the DS4's battery life is poor comparative to other internal battery controllers, eg the Switch Pro and Xbox Elite controllers. I'm confident the XSX's controller will have far better battery life than the DS4, thus mitigating such issues and making the choice to go internal even better.