Only your Hunter has any previous game history for Destiny 2, and that history shows a long hiatus between December 2017, until your recent gameplay. Your Warlock had never been used to play D2 until recently, so they are a brand new character, and will need to follow the New Light quest line to unlock things. There is nothing to fix, as you simply have no prior game history for your Warlock. Your Hunter had completed the Red War campaign, so they at least cleared the basic requirements to be able to play the intro mission for Beyond Light. You are free to pickup the New Light quest for your Hunter, if you wish, as it will help you to get geared up and familiar with the game again. Check the quest kiosk, to the left of the Postmaster, in the Tower. Whatever gear you had in your Hunter’s inventory, and in your Vault, is what you had when you stopped playing back in 2017. The Collections system was not introduced until the Warmind expansion released, in May 2018; so whatever items you actively had on your account, were recorded. Anything you had acquired prior to then, and deleted, would not have been recorded. Deactivating cross-save will not change anything, as your character data is correct, based on your previous game history. Deactivation would only prevent you from being able to use your existing data, while playing on PC.