Thanks for the tips, and turns out I did manage to beat it. All you gotta do is (like you mentioned) get as much food capacity as possible, but then instead of dealing with the enemies in the boss room, just haul ass over to the right side of the room, only eating enemies when they are in your way and would prevent you from moving forward. Then just find the boss, eat it, and you win. Thus, much like you were saying, the difference between victory and defeat is basically just RNG.