I think there are numerous ways to combat antisemitism and supersessionism in my own christian community and I think the first step is being informed and aware of the right theology and truths about the Bible. Being a diligent student of the word is imperative in dispelling wrong narratives about the jews and the land of Israel. I think this Course has done a phenomenal job in explaining to us the right biblical way to view the Jews and Israel.
Another way would be to be bold and speak up when you hear wrong theology about Israel and not be afraid of the backlash now might face, after all the christian community has persecuted the Jews for hundreds of years and now is the the time to right the wrongs we have done In the past. Off course we need to speak truth in love but we need to speak truth regardless.