You’re not even wrong tho. It is a co-op game. There’s no need for “balance”. All they need is to have a reason to consider bringing something other than a single standard loadout.
At the end of the day, the type of player who cares will find the single mathematically best loadout and will just use that, even if they nerf everything into the ground.
What they should focus on is making sure all loadouts have their uses. And perhaps work on matchmaking so the kind of person who plays with randoms won’t get kicked from games for not using The Meta; ideally by matching those non-meta-kickers together so the normal people can have fun.