On occasion I have broken it to the point that I needed to chroot from live USB, but I just chroot and sudo pacman -Syu a couple of hours later and everything sorts itself out. And even if that sounds like a hassle, I can tell you every issue was hardware, I was running endeavor on a USB (not a live env) which is not something I would recommend, because pacman degrades flash memory integrity very quickly, and the only other times I broke it badly enough had to do with nvidia drivers