So 1) not everyone can be wealthy and 2) for a single person to become more wealthy someone else gets poorer.
Clearly relative wealth is a zero sum game. By definition - relative wealth is defined by your difference from the mean, so any change in society's overall wealth is subtracted off.
Absolute wealth is empirically not zero sum. Any disagreement about whether "wealth is zero sum" is either disputing that empirical result, or arguing that the relative wealth definition is more important somehow. So if you're going to argue that you should provide some reasoning.
I think the truth is somewhere in the middle, and that maximising something like median wealth is what's optimal for human flourishing.