“Do you think that God can show up on earth? If so, how would God do that?”
If God had objective existence, then the difficulties [he]'d need to overcome to show up on Earth would be those of the particular being [he] is. Alas, no one knows how God (being real, not imaginary, having objective existence) in fact functions. Does [he] breathe Terran air? Can [he] withstand Terran gravity? Can [he] live on Terran food? Does [he] have special requirements? What about [his] entourage ─ security, drivers, PAs, advisers, medic, cleaners, can they function in Earth conditions?