Unbalanced or not well balance Multiplayer

Hello, me and my friends have given up playing together because we die all the time and make little to no damage at all. We tried it with different builds but the damage seems to be pretty badly balanced when we play together(party of 3). Also the shared loot seems to be also not so well balanced, I mostly get greyed out loot and have pretty bad gear because of it. Please make it better to play in parties:,(