There is no legitimate . Any website claiming otherwise is misleading you. For the authentic experience, play Super Mario Maker 2 on a Nintendo Switch – or wait to see if Nintendo ever announces a true mobile spinoff (unlikely, given their hardware-first strategy).
However, the "3.0.0" in your search refers to the game's final major content update released by Nintendo, which introduced the massive . The Core of Version 3.0.0: World Maker --- Super Mario Maker 2 Mobile 3.0.0 Download