Linux

TL;DR: I'd say EndeavourOS.

Note that as a general rule, the more lightweight a distro is at "run-time", the heavier it is at "configure-time", because you'll have to make choices depending on your needs to get better performance. As an example, probably the lightest weight distro is Gentoo, thanks to compiler optimization and USE flags. But it's a distro with an incredibly steep learning curve. On the other side of the spectrum, there's Ubuntu, which is one of the distros that requires least user configuration, but is also a resource hog. In my opinion EndeavourOS strikes a good balance between the two factors (Disclaimer: I don't daily drive it. I've used it enough to know I can recommend it)