Can I create and apply an environment mask in Unreal?

Hi!

So a bit of context. I am making a vertical slice for a university project. It is in the style on sunset overdrive so I have been trying to use some of the techniques in their workflow on GDC. However they use what they call an ‘environment shader’ multiplying loads of masks to the whole environment. I am quite terrible at using unreal so baby terms are appreciated. There are images below for a basic idea and here is the link to the powerpoint and talk:

Powerpoint: GDC Vault - The Ultimate Trim: Texturing Techniques of Sunset Overdrive

The Talk: GDC Vault - The Ultimate Trim: Texturing Techniques of Sunset Overdrive

Heading down to page 50 starts the talks of procedural brushstroke masks and multiplying them to create an environment shader. I was wondering if someone like me can even achieve this and if so, how? All help is appreciated!