There are those who reckon that the New Testament contains little historical fact, but that has been challenged and thrown out many times.
Even os many – including Christians reckon that john’s gospel is less historical than the synoptic – Matthew Mark and Luke.
Though not dealing directly with historicity Ian Paul makes the case than John influenced the other three.
It also means that John must be earlier, something JAT Robinson of Honest to God argued in 1977.
Enjoy your read.