I'm a PvP main but I also love pve. I play on sensitivity 3. It's mainly because I'm more of a marksman in crucible. Landing headshots with my pulse/sniper rifle. Lower sensitivity for more precision shots( scouts, pulse, and sniper rifle), higher sensitivity for close range combat (shotguns, sub machine guns, etc)
I run a sensitivity at 7. Just play with your settings and see what works. Also. I’m not much of a pvp player. Mostly pve.