A discovery doesn't have to imply that no living being knew about said thing/ place. It can imply only that the person or the group of people the person is from

A discovery doesn't have to imply that no living being knew about said thing/ place. It can imply only that the person or the group of people the person is from learns about this new thing. At some point in time nobody in Europe had definite proof of how to get to America. You can call "europeans learning how to get to America" something else other than "discovered America", but what phrasing should one use instead? To make the point, literally nothing can be classified as "discovered" under your rules because any alien civilization may know about everything we'll ever find or figure out, and if they know about it we can't have discovered it. Columbus was a murderer and people in America before he got there deserved way better but this type of nitpicking correction is just noise if you don't even say what is a more appropriate phrase.