Alaikumassalam wa rahmatullah,
al-Quddus is one of the 99 names of Allah and means "the sacred", "the holy", "the perfect", "the flawless", "the pure". as-Salam is also one of the 99 names of Allah that means "the source of peace and safety", "the safe one" who harms no one and ensures the safety of His servants.
al-Quddus and as-Salam cannot be used as baby names because they are special attributes of Allah. But with as-Salam, if you remove the "as-" from the beginning then its meaning becomes general and you can use it as a name, see its details here: Salam.
al-Quddus cannot be used as a name even if you remove the "al-" and make it Quddus, because it means "holy", an attribute that shouldn't be used for humans in Islam. There is a difference of opinion on this and you may find some people named Quddus, but most scholars are against naming people with it.