https://www.gamespot.com/articles/destiny-2-forsakens-last-wish-raid-wont-get-a-hard/1100-6462326/

Bungie has announced that Last Wish, the Raid included in the Forsaken expansion for Destiny 2, will not be getting additional difficulties. Several past Destiny Raids got a Prestige mode after they launched, which made everything much harder.

In a blog post, Bungie wrote, "We wanted to create an experience that offered the truest forms of every encounter from day one, and offered some of the most powerful rewards in the game to anyone who could succeed." This coincides with Bungie's decision to transform the Iron Banner and make the mode more akin to "an arms race." It makes the mode more challenging from the get go, but it pushes low Power level characters to grow stronger.