Your logic falls a bit short...
How do you explain that those of us (and there are/were hundreds of millions) who don't believe a thing put out by your religion actually believe in the Trinity???
And since your religion couldn't find the Trinity (and tons of other doctrines) in the scriptures, how did your thinkers come up with the idea??? When??? From whom???
You got it from us. Period.
And since your religion couldn't find the Trinity (and tons of other doctrines) in the scriptures, how did your thinkers come up with the idea??? When??? From whom???
It came down to the Catholic Church directly from her first bishops and priests, the apostles and disciples, silly.