Neomutt tip: To escape space in folder name (e.g., iCloud Sent or Deleted Messages), you can use either \ when defining your inboxes in your muttrc or ^V for your bindings. E.g.:
mailboxes =icloud/Drafts =icloud/Sent\ Messages =icloud/Deleted\ Messages =icloud/Archive
macro index,pager gs "<change-folder>+icloud/Sent^V Messages<return>" "go to sent messages"