Aight, for me to answer this question. Let me get some clarity.
Is Kang “one person” or MANY PEOPLE?
Cuz if he’s one then you’re right, I guess nothing much more.
But if the latter
If there's 10000000 multiverses, there's a Kang in every one. The OG Kang figured this out and figured out how to jump universes, and put together a GANG that can also universe AND time jump
That's the problem. You can kill a Kang and another Kang will show up 10 minutes earlier. But that Kang is from the future that watched exactly how you beat the other Kang, and now is fighting you weakened and will knowledge of your skills... Then you kill that one and 45 more show up. Or show up to your grandma's house to kill her before she had your mother...
Took ant-man 2 hours and change to beat one with little to no powers.. There were 1000 more in that last scene, some way stronger.. Kang could be a force literally forever in the MCU and never truly die
Unless of course a white woman files some charges