My system idles about the same with steam(Yes, I checked power consumption), but I have seen times when even with steam doing nothing that multiple web helpers where just eating resources.
I am sure something was recently patched, because I remember within the last month steam was hogging. Not to a point that even my old media center has issues, but still.
Steam was "closed" (to the system tray).
I got to thank epic game store. The boycott and real life stuff have effectively decreased the number of games i play to almost zero. Not really following the gaming scene lately (it is kind of dead). Only thing i want is Cyberpunk 2077 for this year. Who thought i would even give up on Borderlands 3 even if it came to Steam.