"Romans" (aka Epistle to the Romans) wasn't even part of Codex Sinaiticus, circa 330ad
reference - https://www.die-bibel.de/media/articles/pdf/6010_Leseprobe.pdf
https://en.wikipedia.org/wiki/Codex_Sinaiticus
This was nearly 300 years after paul's death. It had the Epistles of Paul, but somehow didn't have Paul's Epistle to the Romans.