MangoHud can be installed either as a system binary using Package Managers, or (perhaps more conveniently) using Flatpak's.
Certain Linux distributions do not allow* mutability in the system directories - as it is in case of my Fedora Silverblue.
Additionally, if the user happens to use Steam as Flatpak (which is a really solid choice and may result in better stability, with fewer issues to worry about system-wide), then it might be the easiest to install MangoHud the same way.