To me, the biggest contrast here is T'challa appears as a grown man in his vision, while Erik appears as a child. Both reflect their inner mind, their core emotional state.
As a man, T'challa is emotionally honest about his grief and the fact that he’s not ready to let his dad go. Erik, on the other hand, says he’s accepted his father’s death, that “It’s just life around here”, but his appearance as a boy suggests that it’s a lie told from immaturity, one that comes from the belief that tears are a sign of weakness.
Their reactions after waking up from thier visions further add to this. T'challa is smiling. He’s overjoyed to have seen his father. While he still misses T'chaka, he’s truly at peace with his father’s passing. Erik is in distress when he wakes up, confused, and maybe a bit disoriented. The absence of his father was a huge blow to him, and the flood of memories that the vision brought back were too much for him. They left him emotionally wrecked.