Changing Texture Size in game to specific values, the workflow?

I’m trying to determine how UE works with Texture sizes and memory consumption scalability.

Currently lets assume all my textures are 4K and 2K (some even 8K) and this occupies X amount of Vram per level load.

I am also avoiding usage of mipmaps because given the nature of my game they are not that useful to me ( i.e my camera is always locked to a certain distance and perspective) and i’ve also heard that mipmaps can occupy more Vram.

So what I want to do is for the player to have a texture quality option that would automatically decrease or divide all the textures (or the ones I had specified) by half so instead of
4K-2K it will be 2K -1K and so on.

Sort of like LODs for texture but pre-determined by the developer.

Example I may not want all 4K textures to be halved so I need to specify this during the dev process. What’s the right way to approach this? I know UE4 has engine scalability options but from what i gathered I don’t like it when the engine decides what to scale down for me. I want to have full control over the texture sizes myself and how they scale down.

Edit: I can imagine a scenario in BP where I tell UE4 to take all textures starting with X_ or Y_ and divide those by half when the player tweaks Option A.

Also I assume the engine can automatically divide the texture by half, although I failed to find the option for it.

Any thoughts?