Got back into the game after shadowkeep , do i have to do old campaign at leg dif ?

[surreal glade]

I want to do beyond light and witch queen campaign to unlock stuff , is there any point in doing them at legendary difficulty ?

[wary delta]

Beyond light won’t have a legend mode. WQ on legend will give you some more triumph score, an emblem, and the choice of a badly rolled exotic at the end.

You can also do normal mode first, and then redo it on legend for those rewards whenever you want.