I guess I'm smart enough to install opensuse, but dumb enough that I somehow got slow pacman.
I kid you not, on my hardware zypper is the fastest between ubuntu apt, fedora dnf, and arch pacman. dnf was the second-fastest on my hardware, with apt and pacman being pretty sluggish
I've also used portage which was even slower, but probably not a fair comparison considering how much more complex it is.
In the grand scheme of things the difference between C, C++, and Python isn't meaningful when operating over a network (edit: for a single-user system). It's very likely that the difference for thread OP is just caused by weaker connections to specific repos.
We're talking about a package manager, not a game, network server, etc. On a basic level the package manager only needs to download files from a network and install them (OS syscalls for reading/writing files, these are exposed C functions or assembly routines), or delegate to a specific package's build setup (which will also likely be written in a compiled language)