This deck is pretty much invincible now with Xyzs. They used to have a problem with being vulnerable if their backrow got removed and if their normal summons/Oyam got interrupted. But now they get to clear opponent field and have big beaters instantly. I don't know how to even think of beating this. The formula of floodgates and backrow removal isn't cutting it anymore.
nah just take a breath and think about the duel calmly;
*if they get an xyz then they can't activate the counter trap
*Oyam only copies original atk, any buff in your monsters is enough to get over it.
*Take each monster out one by one; it is clear which one should be priority. They can't recover stuff from gy.
*Poke them each turn make them waste their oyam and drowning in random weak monsters