TFO but after becoming Optimus Prime, anyone who didn't know the infamous troublemaker Orion Pax makes theories about how this new Prime came to be and it ends up becoming a game of telephone mixed with projection where all the theories are basically Optimus' origins from other continuities
Working class saying he was just a regular hardworking (cogged) bot working in on the docks
Scholars take notice of how smart he is and some have heard he used to frequent the Archive so they say he must have been an archivist there. Some taking it as far as to say he might have been a pupil of Alpha Trion or some head archivist for some time shortly before Sentinel's betrayal
Some enforcers (specially some trying to clean their image), claiming he must have worked as an enforcer and that's where he got his sense of justice from
Students at different places run with the idea that he was a student somewhere (every academy points at a different one) and was either top of his class or hear he used to cause trouble so he was failed and kicked out but his noble spirit and diligent character lead him to the Matrix
Some high caste bots trying to convince themselves Primus wouldn't have just given the Matrix to any bot, so surely he was some sort of secret Primeling, raised in secret by the original Primes to one day inherit the relic
Nobody even considers him being a former cog less miner