if you press slash, tab, then enter, you can automatically leave squad. Also if you have auto-join on but in a critical moment where you did not do enough dmg, then having /squad-create is a good idea since then nobody can join ur squad(as squads are set to private when first created)
So, for looting as a squad, all squad members need to deal more damage to increase the overall average damage of the squad, and secure a guaranteed loot. Oh, that's why my squad can't loot sometimes because its either half of the squads aren't participating or have bad overall DPS as a squad.
Welp now Ultra mobs have been made normal mobs, meaning that only 4 players or 2 squads can loot them, so getting ultras is significantly more difficult now.