I found a semi fix that boosted my fps in some areas but not all. Apparently, Destiny 2 has an anti cheat but does not work correctly as it tries to stop program overlays like Xbox game bar, msi afterburner fps counter, etc. All I did was go into radeon settings and disable the radeon overlay and Xbox game bar. My fps boosted by a solid mark but i still get low fps in some areas. I have an rx6800 and this worked for me. I'm guessing their anti cheat was working so hard to try to stop the overlays that it just killed performance. Hope this helps.