The creator-god of the Transformers was also the Lord of the Light, dedicated to opposing his evil sibling, Unicron. Unicron and Primus were both planet-sized, and Primus eventually became the Transformers' home planet, Cybertron. Or more or less. Like most major DC and Marvel characters, Primus has a whole lot of different incarnations in a whole lot of different stories. The key word here is "planet-sized." Even theoretically infinite strength is only going to do so much when you're not much bigger than a really fat human and your opponent has his own gravitational pull.