https://wccftech.com/destiny-2-content-locked-dlc/

Destiny 2 has recently received its first major DLC, Curse of Osiris, adding more content to the game developed by Bungie released a couple of months back on PC and consoles. Sadly, it seems like it also removed content for those who haven’t bought the DLC.

According to reports, the Destiny 2 Curse of Osiris DLC prevents regular access to the prestige Raid, Nightfall, and Trials, which could all be accessed prior to the DLC pack’s release weekly. Apparently, all three activities have been moved to some sort of DLC playlist. Additionally, this also prevents players from obtaining all achievements and the PS4 version Platinum Trophy.