So basically, I just got a steam account and started playing Destiny 2 on my computer. My original account that I would play Destiny 2 on is on my Xbox. So I decided to do the cross save feature so I can save my stats on both platforms. All my loot and stuff is on my steam account but the campaigns that I bought on Xbox are not there and it says I have to buy it again. I bought Forsaken, Beyond Light and The Witch Queen all on Xbox.
11 Answer
Campaign licenses are per platform. If you bought them on Xbox you will need to buy a game expansion again on Steam.
Currently (Witch Queen / Season of the Risen) the campaigns you mention are in the Destiny Content Vault.
This is detailed in the guide
DLC licenses, such as Beyond Light or Shadowkeep, do not transfer between platform accounts with Cross Save. Players who wish to access DLC on platforms they play on will need to purchase that DLC on that platform.
The existing answer to this question has more details Destiny 2 cross save between PC and XBone, do I need to buy expansions for both
