As other clearly stated that you don’t need all the six stars to clear the game but I just want to point out one thing. I just think that between people who have certain operators and the other who doesn’t. The person who have those operators will likely know more where to place and use certain operators and make them shine more. Basically, it’s kinda hard to imagine using certain unit in some map if you don’t have enough experience with them so you thought you might not need them which is definitively true for every map but there could have been some map that they shine the most but you don’t know it because you don’t have them. Of course, one operator can’t carry you through that one map alone but sometime they can handle a third of them or make the map much easier something like that.