Most of Scripture isn’t concerned with eternal life.
Most of Scripture is concerned with the relationship God’s people have with him. Eternal life is part of that, but it’s not the whole thing.
It’d be like a man and woman thinking marriage is all about where they’re going to live afterward. You don’t get married because you’ll be able to consolidate your housing. At the very least, you get married so your identity is legally tied to another person.
But we still use that language, that language of a housing arrangement. “Living together” is shorthand for sharing our lives together.
We’ve kind of done the same with God. We use “eternal life” as shorthand for sharing our lives together.
Eternal life is just part of the marriage, not the marriage itself.