How to remove flicker from video?

I've got tons of flicker in this deferred rendered video: https://youtu.be/bKYN5tQ5kHM

I rendered it out at 4K resolution to try and reduce the flicker but it still looks really bad. I need to use deferred rendering because I also want to use SSR and the new Post Processing Effects stack (color grading, AO, bloom, etc..) and as you can clearly see there's a ton of flickering in this animation. I've tried different settings, but I can't seem to get anything to work.

Any help is MUCH appreciated!