This trial is for diffuse midline glioma and DIPG in patients 2-29 years old. They can be newly diagnosed or recurrent. It tests the drug Onc-201 with either Paxalisib or Panobinostat. Onc-201 by itself has the best effect on these tumor types so far, but not good enough. Hopefully adding another drug will make them work better, and this is a great way to test the combinations. Nobody gets placebos, they are testing what is thought to be the two best drug combinations against each other.