This is kind of a crazy story to me, and likely pointing to other issues. The "4GB just to run the OS" is probably just macOS preemptively caching... and all Macs use swap extensively so using e.g. 10GB of memory actively is totally fine. I've run out of memory before, but only with serious usage (100s of tabs, VSCode, a 100 MB+ pdf open, etc), and even then there was no actual crashes, I was told that I was using too much memory and suggested some programs to close. What was the "darkroom-alike" program?