Is it not widely agreed that the Nativity stories (present in only 1 or 2 of the Gospels) are fictional embellishments? To reject an historic Jesus based on inconsistencies in the Nativity stories would be like rejecting an historic George Washington if the cherry tree story were proven false.
An historic Jesus seems like a near-certainty to me (if only via Occam’s Razor); the question is what “supernatural” powers did he have? All Gospels agree he was a very adept healer. I find this believable without supposing any miraculous aspect: psychosomatic ailment (e.g. “possession by demons”) was common in that society, and Jesus was a powerfully charismatic hypnotist/exorcist.
The Gospels have internal clues suggesting they’re based on fact. As one example, consider Jesus’ baptism by John. A fiction writer who wanted to emphasize Jesus’ greatness would probably have Jesus baptize John! (BTW, can anyone address my ignorance about evidence for John the Baptist’s existence outside the Gospels?)