Is there a way to give my machines an advantage in a fight?

When challenging the Underground Arena as 9S, you are forced to use machine lifeforms to do your fighting for you. You are able to choose from any machines you've hacked in the past from this list, but is there any way to have an edge on my opponents?

That is, do any of the plug-in chips I can equip help me in this arena or is there anything else I could do to give myself an advantage?

Unfortunately, other than just hijacking and unlocking better machines (assuming you haven't unlocked them all already), there isn't anything you can do to make your remote-controlled machine any stronger, as, according to a user in this thread, even plug-in chips don't affect the machine you control.

Already tested the chips, attack, crit, hp, def, even hijack chips have no effect on your machines stats in the arena. Your character's level and the difficulty settings are the two things that [affect] the stats.

On a related note, there are a handful of machine types that users seem to suggest most frequently using to beat the higher tier fights. Quite a few users have suggested the Small Biped (equipped with an axe) or (unbelievably) the Small Stubby, which apparently does a ridiculous amount of damage with its headbutt. Another one I've seen suggested is the Small Flyer, which is shown in this video beating the S rank battle.