Chromium is C++, i.e. native. The amount of memory used is a separate issue for the most part, and any language or execution environment can use a lot.

Ah okay thank you for the correction. I had heard all this talk about how Electron is based on Chromium which is why developing with it tends to create memory intensive apps or something. Happy to be wrong on that.

Yes, Chromium is native, but apps built with Electron are written in (or compiled to) JavaScript or WebAssembly, so not native, which uses more memory. Since Chromium is a full web browser it has a kind of minimum memory use which is higher than simple Electron apps would take if they were rewritten to be native. But if you're making a browser, you're going to need all that anyway.