Personally, it depends on what kind of story you’re going for.
Power fantasy can, in the right hands, be an exceptionally powerful tool if you want to take a nobody and suddenly give them effectively limitless power; what will they do? Many people say they have good intentions but human nature befalls us all and absolute power corrupts absolutely.
One of the most common answers is to create a utopia with fair and equal treatment. But there’s a problem with that… one man’s utopia is another man’s hell; one of the major problems of course with peaceful coexistence between radically different people and cultures.
I’d add a corruption mechanic and lock certain late-game choices behind it. If your corruption is too high you’re not going to create a peaceful, egalitarian society because you’re too busy dominating or subverting existing systems.
Another way to use power fantasy as a powerful tool is to have the MC start to slowly slide down the power scale as they progress. Someone who once had unlimited power is going to falter and failure, potentially, makes more of a story than unlimited success. Does the MC despair over lost power and try constantly to regain it? Or do they accept their new limitations and start anew?
And on that note, what happens if their powers return? Who do they become?
To me, all these details matter and considerably so. We live in a world with consequences and pitfalls. In my humble opinion as but a man, fiction should be no different. Everything is made, in literature, to tell a story and to make readers reflect on what they read as it applies to reality.