I wouldn't agree with concluding that we have "no reason", because:
- we may have independent reasons for believing in God's existence
- that wouldn't be a sound argument: you'd need "no reason" as a premise to conclude "no reason"
This may be one reason for believing that God doesn't exist, but that isn't the same as having no reason for believing that God does exist.
A conclusion that would fit better into the structure of arguments would be that God doesn't exist. But you can't (deductively) conclude that from those premises, because that would be a faulty generalisation.
As an inductive argument, however, that seems to be a reasonable conclusion:
P1. Every instance of consciousness/intelligence that we’ve observed requires something material.
C2. Immaterial consciousness/intelligence doesn't exist.
(From which you can trivially deductively conclude that God, as an immaterial conscious being, doesn't exist.)
If you want a sound deductive argument, you could use something like the following, instead:
P1. If we've only ever observed instances of something being one way, there's unlikely to exist instances of it being another way.
P2. Every instance of consciousness that we've observed requires something material.
C3. There is unlikely to exist instances of consciousness that don't require something material.
P4. God's consciousness doesn't require something material.
C5. God's consciousness (i.e. God) is unlikely to exist.
Whether the premises are true is, as always, subjective. But I think you can make a good case for those premises, and the argument is valid.
This obviously isn't as strong as "God doesn't exist" or "we have no reason to believe God exists", but it could be considered evidence against God's existence.
You could similarly add "is unlikely" to the problem of evil / suffering to create premises that are harder to object to than the original premises, at the expense of a weaker conclusion (e.g. "if there is suffering without an apparent justification, an all-powerful all-loving being is unlikely exist").