The compile times are quite OK on relatively modern hardware. I’ve been using a Ryzen 1700X up to last week, and except for WebKit I had no reason to complain. On my slightly dated Haswell laptop (from 2016) they are now starting to get on my nerves, but it’s still tolerable.
The only exception is WebKit, which takes forever to compile and which also tends to get installed multiple times, in slightly different versions (one version for Evolution, one for Liferea, one for Epiphany - and yes, those 3 programs all belong to the Gnome desktop). I’ve now set up ccache just for WebKit, but haven’t had to install a WebKit update since, so I have no idea how much the ccache helps…
Sorry for going on a tangent here. Back on topic: The setup for Gentoo takes as long as you are willing to invest time into it… The more time you invest, the more customized the system gets.
I’m currently running Sway window manager, with a ton of other not-so-usual tools (some of which I wrote myself, like my status bar application), and I’m really happy with how my PC currently feels. My desktop looks like it just escaped the early 1990s, but it’s so fast and just doesn’t get in the way ever…