Moin,
Why?
What looks like a relief to you means that I have to remove an icon from the taskbar.
When you boot into the new system for the first time, you are offered CachyOS Hello. If you look around there, which I think is important, you will also find the tools for installing software.
After a few days, you can then set up your desktop in the way that suits you best, because that’s the great thing about Linux 
And no, Octopi is not the default, because, as in all Arch Linux distributions, it is pacman on the command line.
I don’t use a GUI package manager, I only use paru on the command line.
The way a distribution is installed and the various desktop environments, KDE, Gnome, Mate, etc., are preconfigured is only a suggestion, and after a short period of familiarization, the user adapts it to their needs anyway.
Also, if you want Octopi as the default in the menu bar, then the next one, A and B, or X, no, better Y.
So use the first entry point, take a look around, and then design your desktop environment the way you want it—that’s Linux 
With kind regards
Bernd