If you want a super-light subnotebook without having to settle for the super-slow Core m series, then the Comet Lake-U-powered Portege X30L-G should do the trick so long as you can accept a few compromises along the way.
https://www.notebookcheck.net/Dynabook-Portege-X30L-G-is-one-of-the-lightest-Comet-Lake-U-laptops-you-can-get-right-now.465773.0.html