I've had to work in some gnarly monorepos where pulling the dependencies down itself took an hour and a hundred gigs. Local builds were not fast. I usually ended up hacking the build system to build individual projects manually and copying things where they needed to go. sigh much much happier now that I'm living in a smaller repo.
Reminds me one of my past colleagues who worked at some_proprietary_compiler with so many tests for corner cases that it took 6 hours for each build on a top enthusiast grade PC each person in a project was provided. Also the presence in office for 8 hours a day was mandatory, imagine the whole team spread around the place for the most part of the day doing nothing with an excuse "I'm compiling!"