as an onlooker who doesnt know much,Why would anyone's nickname/title be upper land/country? You overcooked the suugo science bro + if you're implying he's was an ethio-semitic speaker then your own argument humiliats your point. If we say that he got his title (badlay=upperlands/country) by conquering the highlands as you said then he must've been a lowlander himself (meaning a somali speaker) because it won't make sense otherwise.
So yeah my etymology and @Three Moons alternatives make way more sense then your suugo science.
this is a strong argument to be fair