Well, two can play at this game....
"Kosmos" means both the world of mankind
and the world as part of creation, but context determines which meaning is appropriate.
Matt 4:8....
"Again, the devil took Him to a very high mountain and showed Him all the kingdoms of the world G2889 and their glory".
"The world of mankind" created kingdoms.
Matt 5:14..
.“You are the light of the world. G2889 A city set on a hill cannot be hidden".
A light to "the world of mankind"....not the planet.
Matt 18:7...
“Woe to the world G2889 because of its stumbling blocks! For it is inevitable that stumbling blocks come; but woe to that man through whom the stumbling block comes!"
That is woe to "the world of mankind", earth's inhabitants...you can't stumble the planet.
John 1:10...
"He was in the world, G2889 and the world G2889 was made through Him, and the world G2889 did not know Him."
Jesus was in the world, among humanity......the world (planet) was made through him, because he was at his Father's side in creation, but since he was "with" his God at the beginning of creation, "kosmos" could also mean the world of mankind here....
The world of humankind did not know him because the devil misrepresented him through his minions....and still is, trying to make him into something he never was.
So you see you cannot be arbitrary in your definitions.....dig deeper. The Bible explains itself if you let it.