Since EndeavourOS is only just over a dozen packages on top of Arch, it would be a challenge to find documentation for Arch that does not also apply to EndeavourOS as well ( beyond the initial install ).
The only EndeavourOS specific issue I can think of is that you may need to update the EndevourOS-keyring package before doing a system update if it has been a really long time since the last one. This would be when you have to update the archlinux-keyring package as well so even then the Arch docs get you most of the way there.