the devas all also seemed always conected to natural forces like deva of fire etc so maha brahma would be a deva/brahma connected to the physcial universe at least 10.000(which was the number given when people reffered to maha brahma in the sutras) world systems of control would be an accurate representation of that which is ofc the lowest brahma plane but things inside it would be his sphere of influence(ofc lesser brahmas would be his staff)(with mara being like a big shareholder in it ) .i also heared that a brahma or deva can take physcial shape by manifesting a course body so maybe that is how the idea of an allmighty etc creator began to circulate or a brahma of maha brahmas retinue got reborn as human re collecting his past live which is think is what may have been jesus after all what he seemed to have taught were the brahma viharas(if that guy even existed).this is just what id find most coherent and easist to imagine for me but i am not an expert so i hope to find some educated guess on the subject or even answer.i was using the sutta center translation.
A Quest to Recover Buddha's True Teachings