I’ve had the issue since 9.0.5 and it’s related to a change in the anima stream graphic in the locations you mentioned. SoA is a nearly unplayable slideshow, and affects my performance the most. There is not really a true fix, it’s a graphical issue on blizzard’s side that they will not address. Some PC users had the problem, too, and they stated they would not fix the asset causing it even though they were aware of it. Everything I’ve tried doesn’t improve the issue at all. Using the FSR and resolution upscaling others have suggested in other threads didn’t really improve my frames much and made the game look like extreme potato graphics. Way too gross to look at on a retina monitor lol. You may be able to gain 5 frames give or take with some adjustments but lose a lot of quality and the conversion isn’t really worth it to me. Setting the graphics to 1 doesn’t change anything.
I also get the extreme drops on tarragrue in the raid but that is a separate issue that I don’t think anyone fixed, either.
You can probably find some other relevant threads if you scroll through this forum. Maybe some suggestion will help you enough to improve your experience a slight bit.