Even that isn't a 100% answer haha.. in that link it still says "⋙Are third-party streaming and communications applications completely broken by this security feature? No. Players may stream Destiny 2 PC using supported modes within the streaming software (e.g. OBS, XSplit, etc). Communication applications such as Discord and Mumble will work normally except for the overlay of their UI in the game." so it seems like you can have discord open, the overlay part just won't work