Reference (and set) specific pixels in a Texture or RenderTarget

If I knew how to use C++…
OK, I need to be able to store massive collections of integer/float values in a texture/rendertarget to use for heat-mapping, and be able to pick up large sections of those textures and be able to reference each pixel in a section. There’s a “read render target pixel/uv” node that seems to do nothing. It’s supposed to read out a 0-1 int or a 0-1 float, but currently will only read out all 0s or all 1s (there’s no variation when testing).
Ultimately I needed to be able to pick up the pixels in a radius around a player position and feed back what the average pixel value is.

I had built all of this before realizing that I can’t actually use it to retrieve/store any data outside of the material graphs. A full 24 hours of internet scrounging and I’ve come up with nothing except that I really need to learn C++ and figure this out on my own. But I am incredibly impatient, and hopeful that the dev team can do this quickly while I aim my efforts towards something else so there’s no time wasted.

I had commented on this thread about using textures to handle large amounts of data before, but I didn’t actually know there was no ready means of doing anything like it:
So my bad…