As much as I dislike KDE, this is just not true. Perhaps you mean your whole system idles at 2GB including all other running services?
To anyone new to Linux, I recommend sticking to Wayland. Gnome if you're familiar with MacOS, KDE if coming from Windows. Use a popular distro with good documentation online (Ubuntu, Fedora, Arch).
Don't worry too much about memory. Just about anything will be lighter than windows. I've had friends choose the absolute worst X11 desktops because it's "light" then run into all sorts of multi monitor issues