Christ Death is Limited to them He knows as His Seed, not all mankind Isa 53:10
10 Yet it pleased the Lord to bruise him; he hath put him to grief: when thou shalt make his soul an offering for sin, he shall see his seed, he shall prolong his days, and the pleasure of the Lord shall prosper in his hand.
Is the serpent seed His Seed also ? Gen 3:14-15
14 And the Lord God said unto the serpent, Because thou hast done this, thou art cursed above all cattle, and above every beast of the field; upon thy belly shalt thou go, and dust shalt thou eat all the days of thy life:
15 And I will put enmity between thee and the woman, and between thy seed and her seed; it shall bruise thy head, and thou shalt bruise his heel.
Now Christs Seed in Isa 53:10 is no doubt the woman's seed of Gen 3:15