Just add the endeavouros repository.
Add this to your /etc/pacman.conf:
[endeavouros]
SigLevel = PackageRequired
Include = /etc/pacman.d/endeavouros-mirrorlist
And create a new file named /etc/pacman.d/endeavouros-mirrorlist:
## Germany
Server = https://mirror.alpix.eu/endeavouros/repo/$repo/$arch
Server = https://de.freedif.org/EndeavourOS/repo/$repo/$arch
Server = https://mirror.moson.org/endeavouros/repo/$repo/$arch
## Sweden
Server = https://ftp.acc.umu.se/mirror/endeavouros/repo/$repo/$arch
Server = https://mirror.linux.pizza/endeavouros/repo/$repo/$arch
## Canada
Server = https://ca.gate.endeavouros.com/endeavouros/repo/$repo/$arch
## China
Server = https://mirrors.tuna.tsinghua.edu.cn/endeavouros/repo/$repo/$arch
## Vietnam
Server = https://mirror.freedif.org/EndeavourOS/repo/$repo/$arch
## Singapore
Server = https://mirror.jingk.ai/endeavouros/repo/$repo/$arch
Server = http://mirror.jingk.ai/endeavouros/repo/$repo/$arch
## France
Server = https://endeavour.remi.lu/repo/$repo/$arch
Import the EndeavourOS key:
sudo pacman-key --keyserver keyserver.ubuntu.com -r 003DB8B0CB23504F
sudo pacman-key --lsign 003DB8B0CB23504F
Then update your system, forcing the database update (with double ys):
sudo pacman -Syyu
And install eos-hooks package:
sudo pacman -S eos-hooks
There, now you’re using EndeavourOS.
And everything is exactly the same 
Warning: I’m writing this off the top of my head, I have not tested it, and there is a good chance I missed a step or two somewhere…