The crown
For the entire Earth, the crown of the English monarch is symbolic of the power and of the English monarchy and its enduring nature. It also symbolizes how that institution has had a long and rich history which has spanned the history of much of Great Britain.
The press
For Harry, the press is symbolic of what's wrong in the world. When Harry's mother died, they exploited Harry and his family and used Diana's death to cynically pump up their own ratings. The press symbolized evil in the world; they did bad things in Harry's life and influenced it in a negative way.
Meghan Markle
Meghan Markle is symbolic of Harry's lifeline and his savior from a life which he hated--a life in which he never felt fulfilled and a life in which he never felt whole. Meghan helped Harry escape his situation and lead the life that he wanted to live.
The United States
For Harry and Meghan Markle, the United States is symbolic of a fresh start. Harry had lived all of his life in Britain, where he attended to royal duties. But Britain constrained Harry and made Harry feel stuck. After he moved to the United States with his wife and child, Harry essentially started a new life, something which he had constantly craved.
Fame
Prince Harry's memoir is an allegory for how isolating being a royal and famous can be (and, as Harry later learned, the life of a normal person) isolating. As Harry's memoir shows, that kind of isolation can be exceptionally damaging.
