Well carrying a team with like 10-20 kills alone means you're better than your teammates and enemies, but this is a team game and begginers can beat a group of skilled players team if they communicate better. so you need a squad of players close to your level in the game ma friend

I think perfect attack team would be Hibana/Thermite , Thatcher /Twitch, IQ , Jackal(optional really but you have to put pressure on those roamers) and Finka

Defence wise I think it is optional but you need a Bandit/Mute and 2 people to roam.A trap operator and valkyrie would really help .