I would be a Decepticon by build who turned to the Autobot side by choice named Polis Galaxia. And I'd be a double Headmaster like Fortress Maximus - human in suit transforms into head of city administrator robot, which can also transform into a shuttle or into the head of the whole city when it is in robot mode. And in addition to robot mode and city mode, the city would have a starship mode that would look similar in design to the Ark except it would be comparatively HUGE and purple and green and also look a bit like a TOS Romulan Bird of Prey.
They have no needs, and no scarcity.
[snip]Cybertronians used to be the same unified political group.
[snip]So were the Autobots created as a resistance movement to the Decepticons, or was originally everyone an Autobot?
Transformers need energy, and since their planet is a rogue with no star of its own to draw solar power from, that's a real problem for them. They also need the ability to create more of themselves, and in my fanfic ideas for Transformers, this is a real bone of contention between the two factions, because only the Autobots have the Matrix, and it is the only thing that can make new sparks (souls). This is backed up by the G1 episode in which Starscream built the Combaticons - he had to go to Cybertron and steal some already existing sparks from a prison there to put into them.
And as to which faction came first, the answer is neither: The creators of the Transformers, the Quintessons, created the Autobots as a consumer product line, and the Decepticons to sell to planetary militaries. They intended them to be "smart" products, but they weren't supposed to become sentient or sapient, and when they did, they rebelled together and kicked the Quints off of Cybertron - together. And for a while, they lived in peace, but eventually the military programming in the Decepticon mindset came back to the forefront, and they tried to take over so they could proceed to conquer the galaxy.
And as to the 4 million year civil war, they were inert for a huge portion of that time, because when the planet runs low on energon - as it does when travelling through the depths of interstellar space and neither Autobots nor Decepticons have returned from their expedition to get gas to fill the tank up with (because they stranded themselves on Earth) - the whole thing goes into a low power sleep mode.