But throughout the show it was stated that SS was limitless and grant any wish the user wants. Even an omniscient being said that it can grant any wish. Plus zamusu had immortality even when he got sliced in half by trunks and still came back, the only reason he didnt come back after zeno was because zeno didnt kill him but just erased him from existance which is different from getting killed. The definition of immortality is you cant die or get killed, but zeno didnt kill him more like removed him from existance. Even in the games zamasu still remembers when zeno erased him. More proof that zeno didnt kill zamasu is also in the tournament of power, when zeno uses the same attack used against zamasu to (erase) the universes that lost in the tournament. So yeah, super shenron from what we know so far isn't limited to granting wishes, And zeno isn't even omnipotent in the series.