I prefer the original origins, but if I put in other origins, I get a hybrid of sorts. What I tend to think is that at one point Optimus was a simple dock worker who had his girlfriend Ariel, but after a while, he decided to move into police work when Ariel was attacked by a few mechs and nearly left her for dead. He gained a reputation in Rodion and got a recommendation to join the Elite Guard Academy, but after a certain incident with his rival Sentinel, got expelled and was forced into the ranks of the regular army as a grunt. However, Orion Pax gained the interest of one old warhorse, Landmine, and began to train him because the new grunt had potential to be a great fighter, if not leader. Orion rose through the ranks and eventually became a commander. During this time, he found Scavanger and befriended him, only for said mech to turn against the Decepticons and become an Autobot spy as well as Pax’s mentor. As the war goes on, Pax becomes the Autobot Commander not just because of his exploits on the battlefield, but also because he pushes through the ranks and shows a talent for leadership that his rival doesn’t have.