How to optimise image effects on Android?

I’m trying to add Bloom, and Vignette to my game. It’s a basic 2D game with no more than a dozen of sprites on screen each frame. I still want to make the game atmosphere look good, so I decided I’d add some image effects, but with only those 2 mentionned effects in the game, FPS drops from 60 to 15 FPS…

What tips, practices, or better scripts to use to achieve those two effects? The build is on the Fastest quality settings too, no VSync, low textures.

Try using the new Post Processing Stack. Only enable the effects you need, and keep everything on lowest settings.

You can also try rendering to render texture and then display the render texture using UI Raw Texture component. This will lower the resolution for the image effects.

Try to avoid enabling HDR.

There are few things to note:
VSync is always on on mobile, your game is already GPU bound if you did not already know, I am curious what device you use. Because these effects should easily work on most phones since 2013, and most flagship phones since 2011.