i've had many instances like this as well, where i felt like i should've done so much more. But difference is i have pellets turned on and i rewatch the replays. and while its crazy to know you can miss at that range, its rng of the pellets afterall. the very slightest movement right before you shoot greatly affects your outcome - and you'll only get to see this affect with pellets on

case 1,2,6 - your low dmg shots seemed to be flicks that involve the very slightest movements right before you shoot
case 3 - shots here did what they were supposed to because these were stable shots and not movement-related shots like case 2
case 4 is the only sus clip imo, but you'll never know if you don't have pellets turned on.
case 5 - your second shoot mightve hit for more, but was only able to register 30 because of opponents hp, so you never actually get to find out how much the second shoot did