Actually, no: If the atheists are right then the theists are 100% wrong. There's no middle ground there or "truth to both sides."
If the theists are right... Which theists? Are we talking about polytheists? Single god but multiple instances of it (aka Ahura Mazda in Zoroastrianism)? Monotheism?
If any one of those are right then all the others are wrong. There's not really any ground that exists between these beliefs.
I think you're confused. The truth you're talking about exists outside of both of those contexts (theism VS atheism).
Religion is just a collection of beliefs that may or may not involve "an invisible man in the sky". Theism VS atheism are mostly orthogonal to the point you're trying to make.
If the theists are right... Which theists? Are we talking about polytheists? Single god but multiple instances of it (aka Ahura Mazda in Zoroastrianism)? Monotheism?
If any one of those are right then all the others are wrong. There's not really any ground that exists between these beliefs.