We talk about the look of this Xfce4 and refer you to the articles on https://arcolinuxb.com, the personal folder and personal alias.
We update the system and we use our ATT to install Openbox and I3wm. This used to be our old flagship combo for years.
If you have an error in our ArcoLinux Tweak Tool or ATT you start the tool from the terminal.
Pacman will/might give a clue why the installation has failed.
There are so many reasons why it can go wrong. Analysis is then required.
Packages not present, conflicting packages, Arch Linux server down, ArcoLinux server down, key issues,...
Removing the desktop can be achieved by removing the most important packages.
It is not always possible for example with Plasma. Then you do a clean install.
You can use our cheatsheet to know what packages to remove
sudo pacman -R ... sudo pacman -Rs ...