Newbie EEVEE animation FLICKERING/NOISE

Hi there! I’ve just moved from maya to blender, and I’m having some problems rendering a simple animation. I’ve created a scene with some characters, a lot of lights (most of them rim lights), a volume cube. In viewport everything works perfectly. When I render the animation, though, I have two major problems:
1. every frame takes 2 minutes to render. How is this possible? in viewport it doesn’t even need a full second to render when I move the camera. (please know I had to remove the characters from the uploaded scene due to copyright issues, the 2 minutes value refers to the complete scene with 5 characters)
2. there’s a bit of flickering everywhere, quite bothering
I know I must be doing something wrong, but I can’t figure out what.
Help!!! =)

link to the scene and the rendered video:
https://drive.google.com/open?id=1UeP5lPgk4CX7FHxmIBy4Ntyc8KjyRWnn

Working in Blender 2.81 on Windows with a Nvidia GeForce RTX 2080 Ti

I also have a few problems with artefacts on shadows and reflected lights, you can find it here:
EEVEE ARTEFACTS shadows + lights inside mesh

In viewport many tricks are applied to privilege fast real-time playback, which is why Viewport is fast and the reason why you could get poor quality, more flickering and even more artifacts than in final render.

If flickers are in source lights using Volumetrics, you can try what I just wrote here:

Thanks! your solution for the volumetrics works like a charm =)

I still don’t understand why viewport rendering is so much faster than Render --> Render Animation (this is the correct way to obtain the final render, isn’t it?)
Is there some way to make it faster?