Someone else in another comment linked to a memory comparison between desktop environments, and there KDE Plasma used the most memory, with GNOME in second place, but I think that the broader point here is that on Windows, you have one basic graphical shell that basically all desktop users are expected to have running. It’s not completely impossible to hack up a Windows environment to avoid doing so, but it’s a highly nonstandard configuration, and stuff is going to break.

Linux has a much broader range of options available, and those are first-class citizens. Some of them are considerably lighter on resource usage than others.

A lot of users aren’t going to cobble together their own ideal environment the way I do, but there are “presets” of packages that are aimed specifically at being light on resource usage. XFCE has historically been one example; they were slow to move to Wayland, but it looks like they’re doing it now. One doesn’t have the sort of “the OS vendor is giving you one monolithic blob that you need to run” the way you do on Windows.