I am currently running KDE Neon 5.27 which is Ubuntu based, on an Inspiron 3551 with an Intel N3540 @ 2.16GHz which is a 4 core Atom,
and 4 GiB of RAM. With this 1 tab of Firefox open, the system is using 2GB of the RAM. I have had no issues running Neon on such a slow system with little RAM, but I don't usually have many tabs or programs running at the same time. Pretty much all the desktop interfaces for Linux run with far less resources and bloat than Windows, I would start by finding which desktop environment you prefer. I have been a fan of KDE for many years now, but try different bootable distros to get a feel for which interface you would like.
Sucuk