Well, I actually agree with you there for the most part, though that's not really conclusive enough for anyone to say "From what I've gone through, there's no doubt"...Which implies there's something you've uncovered that actually points definitively towards it...That's just an educated opinion gathered from your assessment of the probable motivations of people 2,000 years ago..
As it happens I share your educated opinion..I'm certainly not a Jesus myther. But again, on the grounds that it's a sensible opinion that it would've been far easier and convenient to aggrandise an existing figure than make up an entirely fictional prophet when there were lots of that ilk to chose from... Although I'm obviously anti-religion, I'm not that blinkered to think it was created that cynically..
Even L.Ron Hubbard & Joseph Smith weren't stupid enough to invent entirely fictional prophets...Thought they were stupid enough to make them themselves, and both invented a whole opus of silly fictional characters and people believed them, so it's not completely without precedent...
But yes, it's certainly plausible and reasonable to image that someone called Jesus possibly existed, and had some problems with the Romans and was killed...Though there's still absolutely no conclusive evidence for this beyond it being "sensibly plausible."...
From my perspective, the same "sensibly plausible educated opinions" would lead you to conclude that things written about a man hundreds of years after his death, by people who didn't even know him, recounted 2nd hand from some people who supposedly worshiped him, years later, would be spurious at best, and taken with a pinch of salt even today...So when you add in the fact it was 2,000 years ago, when there was a pittance of the verifiable information with which to assess it's worth as there was even in later Ancient times when figures like King Arthur or Robin Hood had probably fictional legends created about them, and I'd say it was a "sensibly plausible educated opinion" that you couldn't really believe any of it...And as such, it's "without doubt" complete bollocks.