Oooh.. the fact you got those vibes is interesting, I only listened to a couple Polyphia tracks and left it at that lol they're super cool though! As for Underoath influences, it's from the two albums after, Define the Great Line and Lost in the Sound of Separation.
I have a few references that I go back to as the main inspiration for my song, and I'm hoping that the influence is obvious I just think they're a neat band