I exclusively use unreal on linux and have only seen it go above or near 32gb during compile or with huge landscapes. But afaik the build system will limit the parallel build processes based on memory.
Also you should factor in just how much the editor can do. Its pretty efficient imho for what it offers, fitting all it does in the rather small amount of ram is impressive. 32gb is not ridiculously high for game development of serious games.
Ram usage in a packaged builds of my game on linux is much lower. The only time I’ve seen high ram usage come into play is compiling the editor or using the editor with large scene. On void linux with a decent size open world with a large amount of foliage and AI characters the editor is using around 4gb RES for me.