I think the point of Endeavor is not all people who are clamored as heroes are good people. He may be good at saving people and he does his job well and that's to be respected, but he is a shitty person. He's the #2 hero and is good at being the hero role from a purely capable standpoint and he does fill the credentials of what their society considers a hero and does do good for the world in pursuing that, but lacks any sort of heroic tendencies outside of his work and is a really shitty person all around.
Which also gives some credit to the Hero Killer's anti-hero angle, since his character is of course a villain but he's doing it for a reason that's not completely wrong, but doesn't justify him or make his views correct either. He thinks there's heroes and villains who soil the reputation of both, and Endeavor is the very sort of person that the Hero Killer hates. People who aren't actually heroes deep down who are parading around as them, people using their powers for selfish reasons and to move themselves forward in society for self-gain, ego, reputation, glamour, personal vendettas, etc. Basically heroes who aren't really heroes, and villains who do evil things purely for their own selfish desires. He puts great importance on people taking on these roles who are working for something bigger than themselves.
I think Endeavor is an important character to have for some of the dilemmas of the show, he obviously has some pocket of love (or maybe more accurately respect) for his son above zero, but that hardly makes him a good father. He's a real shit dad.