Maybe the humans on Earth could have trained daily to eventually be able to create shields with the same structural makeup as Anthozoa. That would be an overpowered shield, considering how Anthozoa survived a drop test of a ton of steel from a height of one metre without as much as a scratch.
This was more than enough to tank bullets. Conceptualising shields was easy, so with enough training, a human could naturally perfect it to the level of Anthozoa if they were taught that.
Similarly, they could also manufacture all the required parts of a gun and then assemble it. Even for a gun, all individual parts were pretty simple for the human brain to conceptualise.
But, Rass had condensed an entire gun. This surpassed the level of a human.
