Bullets are supposed to be lethal to who again in One Piece?

Luffy is immune to musket balls from the first Tankobon. A guy who is capable of splitting warships in two and casually deflects bullets is introduced in Tankobon 6. Zoro upgrades to being able to split cannon balls past Alabasta arc and both him and Luffy explicitly take direct hits comparable to artillery rounds in Skypie and Water 7 arcs.

The high end of the series has guy who can literally move at light speed due to turning into literal ray of light, and can shoots lasers.

Really, anyone who thinks One Piece as a whole is less powerful or "more realistic" than Naruto or Bleach really, really needs to go reread Skypiea arc and refresh their memory on all the things Eneru does. And then remind themselves that Eneru is a mid-series villain in OP who is easily topped by even more absurd characters in the series.