[temo4ka]

No, EndeavourOS is a nice, easy installer for Arch. You use Calamares and either select packages, or groups of packages in GUI, or/and provide a list of packages in a text file for Calamares to pick up during the install. You can even ignore Calamares altogether and just use Live OS to install Arch kind of the usual way, but from a comfort of a graphical environment; i.e., multiple pseudo TTYs, no need to configure WiFi, with a full-fledged GUI browser (Firefox), etc.

Manjaro Live OS can't be used to install vanilla Arch. Manjaro uses its own package repositories that differ significantly from the Arch repos, in terms of versions (which are held back for at least a couple of weeks) and in terms of which packages are available (quite a few AUR packages are present in the Manjaro's repositories).