Yup. My old 1st gen Ryzen desktop system isn’t particularly power efficient, but it idles <50W (I think closer to 25W, but I haven’t measured for a while). And that’s a desktop class chip from 7 years ago with two HDDs and a discrete GPU and PCIe wifi card, so it’s not winning any awards for efficiency. Even at that, it’s barely a blip on my power bill.

An AMD or Intel laptop-class chip should be able to get to 10W or so idle, and not spike too much with basic tasks. And those can be had for $200-300, less if you’re okay with older chips. Run Linux headless and it’ll likely stay below 15W at the wall most of the time.