Ok, please bear with me as I know pratically nothing about ancients especially about this particular type. I see that in all samples they share a common "hole" in the middle. Is this part of the design or it's normal due to how the coins were made back in those days?
Yes, all ptolemaic copper, and many nearby greek, and later roman provincials in the same areas had these. They were called concentric circles. If you look closely, there is evidence of turning, so most likely these were used with pincers to turn the flan on a lathe.
Nope, that would be my BospOREO, Sauromates I of the Bosporus Kingdom. Not huge but not tiny either... 29mm