Destiny 2 is also weird with its very limited ranges and damage fall off. This can also vary quite a bit with two copies of the same weapon if they don't have identical rolls on them. There are also various builds out there that are designed to increase weapon or melee damage in PvP, which allow for two taps or even single shot body shots with some weapons under specific circumstances. The top PvPers understand the game on a highly technical level and setup their characters around these things. Armor mods can be hugely powerful in aiding you in the Crucible.You're right about those nuances. I've been trying to get better at choosing my battles more wisely and disengaging when things aren't in my favor. I'm also trying to work on my hand cannon accuracy. I noticed the guys that can consistently get the 3 tap typically dominate.
Personally, I think all this shit should be disabled to level the playing field to a place where the only thing that matters is your skills. But that's not how modern shooters are built.