Do you have Gamepass? As you know Destiny has joined Gamepass on console, including Forsaken and Shadowkeep. However there is a rumour around right now that Destiny will be joining Gamepass PC on Nov 10th. Just a rumour but fits with Microsoft and Bungies recent blossoming friendship. So if you can wait then you might get lucky?
Hi there. This is not something within Bungie's control—the platforms handle your DLC licenses and there are fees associated with licensing, so each one wants their cut. The only way this would ever happen is if Google, Microsoft, Sony, and Valve all agreed to grant licenses if the customer purchases them on any one of these platforms.