There should not be a Problem with your Mod, if the same components are covered. You might need to turn down the Powerlimit or undervolt. OR raise the Fan RPM.
Since the Asus Phoenix is rated for 170W vs 220W of the 3070. At least the Phoenix has a thicker cooler then a Palit or Gainward 1-Fan Cooler (which doesnt fit 4l cases).
From a Review you can overclock a Asus Phoenix 3060 and still have a quiet Fan Profile...meaning you have some headroom.