Gentoo itself is “just” a very solid distro with lots of flexibility due to being source-based (most distros just deliver the resulting binaries), so if you’re the kind of person that would customize the things Gentoo exposes, Gentoo makes it easier than it would be on Debian or Arch. If not, it’s an added complexity for not much benefit.

The Gentoo installation guide famously doesn’t shy away from explaining what needs to be done, it isn’t just a series of step-by-step instructions. For this reason it’s a great way to start learning this stuff. Even if it won’t explain everything completely, it will surely point at the right direction.