Given that Neanderthal inter-bred with modern humans in Europe Asia, it seems more accurate to think of them as a race rather than a separate species.
“Species” is now a political term. Same for “evolution”.
I am with you. I was taught that as part of defining a species was that species could not interbreed. Or at a minimum their offspring was unable to reproduce. As in donkey and horse.
Search through a concordance online for the word "giant" and it is clear there were specific areas where they lived. Neanderthals.Genesis 6 - King James Version
6 1 And it came to pass, when men began to multiply on the face of the earth, and daughters were born unto them,
2 That the sons of God saw the daughters of men that they were fair; and they took them wives of all which they chose.
3 And the Lord said, My spirit shall not always strive with man, for that he also is flesh: yet his days shall be an hundred and twenty years.
4 There were giants in the earth in those days; and also after that, when the sons of God came in unto the daughters of men, and they bare children to them, the same became mighty men which were of old, men of renown.