LXQt is excellent in terms of resource efficiency and snappiness, although I suspect the person you replied to will have the same issue with it as they stated they had with XFCE (not "refined"?). It's a much lighter desktop environment than XFCE, from what I remember when I last tested them (~200MB vs XFCE's 0.5GB+).
It's a continuation of LXDE which was absorbed into another project when LXDE was discontinued, iirc
It's a continuation of LXDE which was absorbed into another project when LXDE was discontinued, iirc