Gentoo is on the Latitude; it's slightly more powerful, but it's still an eight year old laptop. The big thing that's cut down on compile time is using binary packages by default, only compiling when I either need to because my USE flags are different, or because there's no binary package available. I don't have that many packages installed that take hours/days (and I do mean days, I gave up on the source package for qtwebengine after 3 days of compiling) anymore. Average update takes maybe 30 minutes now, updating weekly.

For a more direct comparison: Same PC, installed Gentoo twice (I managed to bork my install), the source install took 3 days to actually get a GUI, binary install took 3 hours, and there is essentially no difference

I will also say: You can absolutely use your computer while the upgrades are going. Gaming won't be great, but doing office/coding stuff, and watching videos is usually fine