This is accurate, and unfortunately the questioner is going through all the threads repeating naive objections to the legit answers offered by people familiar with aerospace. I know the guy who led the assembly of the JWST/MIRI cryocooler, which was one of a handful of high-risk items on the spacecraft, and all of his team’s time was taken up with assembly, build, integration, and test, not just abstract design. I’ve explained this kind of thing in past threads, but it’s tiresome!