An all-powerful being who is also all-good can't have free will.
Granting that there are a number of different definitions of "omnipotence" (ability to do literally anything, ability to do anything that is logically possible, ability to do anything that is consistent with the being's nature, etc...), we can probably agree that a being who has the attribute of being "omnipotent" generally has the ability to do anything it desires. Once you add the attribute of "all-good" to the mix, regardless of your definition of THAT term, we find that the being's actions in any given situation are constrained to a single option. It (god) must do the most perfect/good action every time. Even if you propose that god is a-temporal and exists outside of time, so that all of its actions occur simultaneously from its perspective, you haven't gotten away from the fact that god could not have taken an action that was less than perfect.
When a (non all-good) being makes a choice, there is a continuum of good/bad options. It's not the case that there only exists a binary set of choices to be made. One could choose the worst possible option, a bad option, a neutral option, a good option, the best option, etc... With a perfectly "good" being however (regardless of your definition of "good"), the choice does become binary. Everything boils down to the "perfect decision", and "everything else". God, being perfect, does not have the option of choosing anything other than the "perfect decision", therefore it doesn't have free will.
It might be the case that the argument will be made that whatever god chooses to do becomes "good" simply by the fact that god did it. Of course this argument makes "goodness" completely arbitrary and meaningless. I will grant that this interpretation allows for god to have a kind of "free will" at the cost of any kind of absolute goodness that means anything.
The overall argument also implies that we live in the best possible world, and it would be impossible to conceive of a universe that would be "better" even to the smallest degree.
Conclusion: Either god is not perfectly good (by any measure that has meaning), god is not omnipotent and cannot take the most "perfect" action, god does not have free will, or god doesn't exist.