Best Settings for smoother Animation Render?

I am getting some flickering on a lot of the background surfaces of my animation and would like to know if anyone has any settings to help reduce the flicker, but also keep the render time reasonable. Here are the settings I used:
1080p
500 samples
combined denoiser
no depth of field
GI 2 bounces
Reflections 2 bounces
Refractions 8 bounces
highlight burn 0
Clipping Masks on

I am also using a fairly large file [~670,000 kb] on a nvidia rtx 3070

https://vimeo.com/649627155

Hmm. Not sure but it could be caused by the light cache. Try with light cache disabled. If it’s smooth then you could either continue working without the cache or you could try e.g. increasing the cache sample limit (file->advanced scene settings), but I’m not sure if it’s worth tinkering with it. The render speed probably won’t be that much different without the cache.