The very same credibility problem that afflicts just about every figure from antiquity that we know about. Do we write off the historical existence of Constantine I because the stories about him contain miracles (seeing the sign of the cross before a battle, for instance)? Pythagoras is right out. And so on.
You should be ashamed of yourself for even attempting that bogus Christian apologetics argument yet again.
Look - none of those other figures in history are known entirely for the supernatural things they did. They are known almost entirely for a whole mass of perfectly ordinary human things which they were said to have done. And in many cases, there is overwhelming evidence of their existence ... often inc. museums all around the world, stuffed full of physical evidence of their actions.
To claim any such thing for Jesus or God is laughable, if not outright disingenuous.
The only source of anything which could possibly be called "evidence" of Jesus, is the NT bible. But that is a religious book composed from various early preaching pericopes, in all of which Jesus is portrayed entirely in terms of the supernatural.
Any non-supernatural actions of Jesus, simply have Jesus walking to some named local place where he then performs a miracle or where he then makes some amazing wise or prophetic saying. So the names of those places and the fact that someone was said to walk somewhere, are just part of the setting for each miracle/supernatural story ... the fact of places like Jerusalem existing, and people being able to walk and talk, is not evidence of Jesus ... those elements are just a necessary part of each story (you can't have Jesus making amazing wise insightful sayings unless he speaks and people hear him!).
That is emphatically NOT the case with any other genuinely "real" figures of ancient history, is it!? No it's definitely NOT!
Which other figures from ancient history are claimed to be real, and yet are like Jesus in being known only from a book of religious preaching, known/famous entirely for their miraculous supernatural deeds and not known to have done anything else at all, where nobody who ever wrote about them ever met them or knew them in any way at all, where their claimed presence on earth had been predicted 500 years or more before in the religious books that everyone believed, and where there is no evidence at all that they ever existed? Which other world famous figures in history are like that?
There
are lots of other ancient figures like that. But they are all gods, devils, spirits and demons of other religious beliefs such as the gods of Greek, Persian and Roman legend of that same time in that same region.