Theories of God and the afterlife differ greatly in their implications for the existence of the soul. Is it logically possible both for God to exist and for there to be an afterlife but for there not to be s soul ?
First of all, we need to be precise about the meaning of "God". By that, I mean the God of classical theism: the Subsistent or Absolute Being, one, absolutely simple, absolutely infinite, eternal and immutable.
On the other hand, regarding the human soul:
Given that we can do abstract reasoning, our soul is spiritual, and not an emergent property of matter.
Given that our soul is spiritual, it is naturally immortal.
Given that our soul is spiritual, it is created directly by God at the beginning of each human being's existence. (Contingent spirits cannot create or emanate other spirits.)
Now, it is clear that God can decide to no longer sustain the existence of a naturally immortal soul, just as He can do with any other created entity. E.g., God could have decided to no longer sustain the existence of former planet Pluto once astronomers demoted it from planethood, and Pluto would have disappeared.
So, for each combination of the existence of God (G, again, the Subsistent Being of classical theism), the spiritual soul (S), and the afterlife (A), I will state its consistency with the fact of abstract reasoning and its logical self-consistency.
G - S - A - Consistency with abstract reasoning - Self-consistency - Note T - T - T - Y - Y - Classical theism. T - F - F - N - Y - Practical atheism: God exists but it doesn't matter. T - F - T - N - N - Afterlife of what? T - T - F - Y - N - Why creating a soul only to annihilate it later? F - T - T - Y - N - How does the spiritual soul pop into existence? F - T - F - Y - N - How does the soul pop into and out of existence??? F - F - T - N - N - Afterlife of what? F - F - F - N - Y - Just atheism.
There are two examples of believe in a God (or Gods) and an afterlife where a belief in an eternal soul doesn't occur.
The first is Buddhism, where the concept of a soul is seen as a misconception of physical life, so to speak. Buddhists are an interesting case insofar as they do believe in the existence of reincarnation and 'Gods', but they don't see themselves as being reliant on those Gods to achieve enlightenment; in that sense they have been described as being atheistic in the past and that does have some merit. That said, it's clear that they are a spiritual people who have a strong belief in the existence of Gods and of an afterlife (in some fashion) yet don't believe in the concept of an eternal soul.
Closer to home, you have Jehovah's Witnesses; a millenial sect of Christianity that don't believe in the existence of Hell, but believe that humans have a choice to follow God and live in a paradise earth forever, or not and face everlasting death. (This is a simplification, but is accurate for the purposes of this question). They specifically believe in God (but not a trinity) and they do believe in a life after death, but put constraints on when it starts and how it's structured. They specifically teach that the concept of the Eternal Soul was introduced to Western thinking by Plato and doesn't have a Christian application or justification in the Bible.
So the answer is yes, you can believe in God, and a specific form of afterlife, and still not believe in an eternal soul. It's just not as common as more mainstream Christian faiths would normally get to see.