Yes. Gentoo is a metadistro - it gives you the tools to create your own Linux OS.
However without binary package repository (which is something that Gentoo's Portage system supports) your system updates will be as slow/fast as your computer can compile.
For lightweight binary distro, I'd probably go with Alpine. I used Arch for a while, but it was too bleeding edge for me.
That said, I've been using Gentoo for almost 20 years. I don't use it for because it can be made fast, but because "Gentoo is the choice edition" and stable rolling releases.