Thank you all for your likes.
Do a Ctrl+F search for "jumpsuit." There are separate versions for male and female; set the disabled flag on the proper one (depends on the gender of your player character) from no to yes. I've attached one that works for females.
Nice alternative approach, biosquid2. I linked to it in the main post.
But could you please zip the xtbl file? It's a text file. So the zipping should save a lot of the 1.9 MB.
Additionally, you gave me a good and easy starting point for a more enhanced version of this mod I had in mind, which will remove most of the "unnecessary" clothing in parts of the game where you are forced to wear something. Like at the start in the white house. I were already looking into the lua files of the corresponding missions, but I guess I thought way to complex.
I guess almost all of it can be done with modifying some of the xtbl files.
I tried your approach. It could possibly cause bugs, because the short animation you have while leaving the simulation is gone. So it seems like something is broken because of the disabled clothing items. If somebody recognizes something else is bugged by it, please report.