I have my own opinionated Arch / niri set up and there's 1155 packages installed. That's 1155 opportunities for a package to be compromised. This is also why I try very hard to avoid the AUR and only use it as a last resort (I use 2 packages from it). It doesn't guarantee safety but the official Arch package repos do seem to have more checks and bounds vs the AUR.
Arch is second only to Guix in terms of supply chain security for desktop distributions, but both still have a threat model that cannot tolerate a single laptop compromise.
Stay tuned for stagex for workstations. https://stagex.tools