@HeyCallMeRed It might give you signing errors, fail fast and not upgrade at all, the command here should prevent that https://wiki.archlinux.org/title/Pacman/Package_signing#Upgrade_system_regularly

Also https://wiki.archlinux.org/title/System_maintenance#Upgrading_the_system lists the usual advice: read the news, look out for changed configuration files, allocate some time do to the upgrade so you have time to fix it if anything breaks, and restart.