Q about arguments for God's existence.

[abaris]

It is absolutely clear that Jesus contemporaries strongly believed that he did things for which there was and there remains no explanation within current understanding.

No. it isn't absolutely clear. Only the gospels, written decades later, speak about it.

Outside authors - at best - acknowledge that there is a group called christians. And the only one directly pointing at Jesus, Josephus, is a known forgery. The Testimonium Flavianum has been demonstrated continually over the centuries to be a forgery, likely interpolated by Catholic Church historian Eusebius in the fourth century.