I contracted for an injection molds manufacturer that used Unigraphics from '06 to '22 as a general sysadmin. I was "adjacent" to NX and never really interacted with it directly (though I orchestrated a lot of silent deployments / upgrades).
It was noteworthy to me that they'd so heavily integrated UG (and customization of UG) into their operations. They started with UG back in the early 80s on a Data General machine. I was told they had proprietary "GRIP" code still in use that dated back to the late 80s.
Seeing as David Weisberg's "History of CAD" is trending today, I submitted "History of Unigraphics" by 3 of the original Unigraphics 7 dwarfs.
The article came out at the end of 2024 ... these guys must all be around 80 by now.
Edit: Unigraphics X SDRC became the system we know today as Siemens NX