How does the Albatross symbolize hope in the rime of the ancient mariner?

It came from nowhere, and it lead the ship and the crew to safety from the deadly storm near the start of the poem. It was considered their saviour. When the Ancient Mariner shot the Albatross, it was as if the Ancient Mariner shot their hope, and this was why he was punished cruelly. As soon as it died, the crew started to suffer from draught, and eventually has their souls stolen, which emphasizes what happens when they lose hope, and reiterates how essential the Albatross was.