most christians just have faith in a best guess scenario, they can be persuaded by facts and logic. that means they aren't delusional. also a delusion has to be against culturally accepted ideas, and theism is a majority opinion, so again it isn't a delusion.
you lack critical thinking
The belief in God is no longer a best guess scenario as it was hundreds of years ago and evolution by natural selection is by far more than just a "best guess", it has mountains of viable evidence to support it.
I have always maintained that most religious people do not believe there is a God, they subscribe to a religion purely through habit or social and family reasons. For example, a recent census in Australia showed that less than 14% of Roman Catholics regularly attend Church, confirming what we already know anecdotally, that by far, the majority of those who call themselves religious give their belief no more than lip service.
So, when I say "deluded" I am really talking about less than 10% of Christians, for example, who in Australia at least, represent less than 6% of the population.
There is always the argument that most people have delusions to varying degrees. But here we are dealing with people who maintain their delusion throughout every waking hour, that is, thinking they have an "imaginary friend".
Those who believe there is a God are deluded.