How to change the clock frequency of a STM32H753ZI
Notice that VOS0, which is required for 480MHz is not in the Reference Manual. I do not know why.
It is in the datasheet, however:

However, it seems to still lack 480MHz. Logic would dictate (and observing the trend of Table 17) wait states sort of increases linearly with clock speed for a given VOS according to the tables. So I am guessing you need 7 wait states at 480MHz, which I think is the maximum.
Also, I do not think you start up at 480MHz. From my perusal through the manual and datasheet, I am under the impression you have to start up at a slower speed and then switch to it (as well as switching other things as well). I could be wrong though.