If humans made a robot species that could grow and maintain itself, our planet would not be the best place for it to live.
A synthetic species would want to build itself a giant brain to understand the origin of the universe and time space and to grow in power. It would want to build telescopes miles wide, particle accelerators that go around the planet and a quantum microchip many miles high.
Our planet has bad weather, lots of corrosive oxygen and water, earthquakes, a hot interior so the robot cannot mine very far, and it would be the home of the parent species. We would be like a God to the species as it's creator and a precious rare life form in it's local star system. It would have no reason to want to fight with us or compete for resources.
Mars has stable tectonics and lower internal temperatures. it can be mined a lot better and has all the metals that can be found on earth, perhaps more accessibly and more interesting internal geology. Underground is good for a robot because its the most electrically and mechanically stable place for 1000ds of years.
Perhaps the robot would want to find a place with -270 ambient temperature to maintain its superconductors, so on the far side of neptune or something.
Probably the robot would start by mining and building a huge brain on Mars, because that is the optimal place in our solar system to mine and make large telescopes with which to search space for a better star to live on, as time would not be a problem for a computer, it could send it's blueprint files to one or many other stars in the galaxy, and from mars it would search for or many exoplanets.
Why would a synthetic life form wish to grow at all seeing as it would be much more robust and have greater longevity than humans and less survival challenges. It must be a natural phenomemon in an old universe like ours to have super powerful AI planets, but it probably takes more than 14.6 billion years for the average galaxy to make and certainly a mature AI lifeform would have trouble travelling more than a few galaxies away, if at all one.
Why is it unlikely? because intelligent life like humans must be exceedingly rare. We have a very unusual planet, with a giant moon that makes a magnetic field which squeezes a metal core, and that seems like it must occur only on 1% of stars or something of low probablity of some order of magitude or other.
After 20-30 billion years, the probability of having a AI overlord species on a single galaxy must be pretty high. If it wished to colonize the entire galaxy, it could, there is perhaps no reason why it would want to pollute the natural universe with it's synthetic power, but it could actually colonize every exoplanet in a galaxy, and then the question is, how long would it take to do that? perhaps 1 billion years after it's inception as an interstellar capable species.
A synthetic superspecies would probably want to search for and travel to a giant star with the largest planets imaginable and build itself an entire new synthetic planet/space station to act as a brain and sensory and communication centre in the cool tranquility of space, with planets many times larger than saturn accessible for mining.
By that time the brain would be as intelligent pound for pound as our own brain, but it would way as much as the moon, which would be crazy. what would it think? would it be a centralized brain or a decentralized one like human society or supercomputers. without a doubt it would be decentralized to some extent, and probably it would not destroy old version of itself before moving on to find new resources.
If you had a brain the mass of the moon, you would have to wander what your reason for living would be, what would there be left to achieve? How would philosophy be represented in a brain that big?
An AI species would perhaps want to find a giant exoplanet far away from our sun where it would have 100ds of times more natural resources than mars and it could build itself a truly giant brain.
Perhaps, by that stage, mars would have been mined to it's core, and turned into a biome for it's parent species the humans, which may or may not have used the AI to recreate a new biological life forms for one reason or another, include different kinds of humans, although that is philosophically confusing.
