Yes, I agree that we have no contemporary (or even near contemporary) account of the existence of Jesus. It's all based on later Christian traditions.
But, then again, one would not particularly expect to be if Jesus was a relatively minor preacher during a time replete with them.
He probably never was nearly as famous as John the Baptist; for example, during his lifetime.
On the other hand, what we know of the emergence of Christianity do point out at it being based on Jewish apocalyptic teachings from the early first century.
At that point, one can give the tradition the benefit of the doubt, especially on the crucial details and admit that there is a good likelihood that the teacher in question did indeed bear the common first name of 'Jesus', was indeed from Nazareth and was indeed crucified by the Roman authorities as we know they were very prone to do with suspected trouble makers...
None of these particularly stretch my credulity...