this is correct, there's even a precompiled kernel (dist-kernel), it works great! and when packages doesn't match your system settings, portage will pull the source and compile them. it's great!
YMMV, I spend a couple of days last summer trying to get a Gentoo install with KDE running and after I changed something which caused a libc recompile, which took over an hour, I was so fed up I went back to Arch.
...granted, my potato only has an i7-6700 Skylake with 4 cores+hyperthreads for 8 threads at 3.40GHz, it's not one of those AMD Ryzen things, but still: I'm not running GNU/Linux because I want to buy a new PC every year.
Portage is the best package manager out of any distribution.
There are no buts. Gentoo is awesome.