There's a bunch of old texts about a Jewish "prophet" called Jesus, who was gathering some followers. As far as I understand, there's no really reason not to believe the person existed.
Then again, all the Jesus lore, there's no reason to believe his miracles were real as those made no sense and there's no real proof besides those same texts written after Jesse's death
This. There is evidence that a preacher called Jesus existed, was crucified, and was well-regarded enough to start a following that persisted even after his death.
There isn't, however, strong historical evidence for any of the magical parts of it.