CS, I never said that Hashem chas veshalom doesn’t care about what we do and that it’s just for ourselves so what’s the big deal if we fail.
What I said is that Hashem does not need anything. This is basic jewish theology outlined in the rambam and everyone else. Needing something means that there’s a lack, there’s an imperfection, r”l.
We are needed in Hashem’s plans. We have a given mission, both individually and collectively. Our avodah is necessary – the most important thing in the world. Hashem gave us a responsibility, and from our perspective it’s not for ourselves; it’s to be mekadesh shem shomayim, to help others, to be davuk bashem, many intentions. From Hashem’s perspective, it’s for our benefit.