Some of the Ancient Greek philosophers believed that the Sun, and not the Earth, is in the center. For example Aristarchus of Samos and Seleucus of Seleucia.
However, the main problem with most of the achievements of the Ancient Greek Philosophy is that, unlike for logic and mathematics, for theories about natural objects they did not have good methods to determine which of several alternative theories is right.
So in the natural sciences there are a lot of questions about which some Ancient Greek philosophers have guessed the correct answer while others have guessed wrong.
Now we know who was right and who was wrong, but at that time this was non-obvious and in most cases the popularity of the alternative explanations was determined more by the rhetoric skill of their supporters than by their agreement with the observations of nature.
Even when the agreement with observations was actually checked, the methods of measurement were seldom precise enough to allow a non-ambiguous decision between 2 theories.
This also applies to the heliocentric theory and the geocentric theory. Both theories had their supporters, but in the end the geocentric theory became the main theory for almost 2 millennia because it happened to be the theory chosen by Hipparchus and then improved by Ptolemy.
Ptolemy made a more detailed kinematic model of the movements of the bodies in the Solar System, which agreed better with the observations of the planets than all the earlier models, so those were abandoned until Copernicus revived the heliocentric model.
Heliocentrist Aristarchus of Samos lived ~310-230 BCE. Archimedes ~287-212 BCE. They shared a lot of years in common. We know Archi knew about Ari, because of his work The Sand Reckoner [https://en.wikipedia.org/wiki/The_Sand_Reckoner]:
"Archimedes then estimated an upper bound for the number of grains of sand required to fill the Universe. To do this, he used the heliocentric model of Aristarchus of Samos. The original work by Aristarchus has been lost. This work by Archimedes however is one of the few surviving references to his theory...."
I was going to make a similar comment, but you phrased it better than I could have. It's easy to say in hindsight that X knew Y, but there's a big difference between knowing something and just suspecting it.
In fact, at the time the evidence for many models was equally strong. So, based on the limited available evidence of the day it actually would have been incorrect to believe too strongly in any model, even the one that we now know to be better than the others.
However, the main problem with most of the achievements of the Ancient Greek Philosophy is that, unlike for logic and mathematics, for theories about natural objects they did not have good methods to determine which of several alternative theories is right.
So in the natural sciences there are a lot of questions about which some Ancient Greek philosophers have guessed the correct answer while others have guessed wrong.
Now we know who was right and who was wrong, but at that time this was non-obvious and in most cases the popularity of the alternative explanations was determined more by the rhetoric skill of their supporters than by their agreement with the observations of nature.
Even when the agreement with observations was actually checked, the methods of measurement were seldom precise enough to allow a non-ambiguous decision between 2 theories.
This also applies to the heliocentric theory and the geocentric theory. Both theories had their supporters, but in the end the geocentric theory became the main theory for almost 2 millennia because it happened to be the theory chosen by Hipparchus and then improved by Ptolemy.
Ptolemy made a more detailed kinematic model of the movements of the bodies in the Solar System, which agreed better with the observations of the planets than all the earlier models, so those were abandoned until Copernicus revived the heliocentric model.