Resize and convert a SVG image using a gimp script ?

[Ofnuts]

You are starting from SVGs. SVG files, being vector graphics,  can be scaled losslessly. If you convert them to raster first and scale next. the cale is don on ratser and not correct.  A good CLI tool to scale SVG as vector and only then output the result to PNG  is rsvg-convert


rsvg-convert --width=400 --height=400 nm-device-wired.svg -o nm-device-wired-rsvg.png


So the 4+x upscale is perfectly sharp;

   

I found rsvg-convert already installed on my Ubuntu so you probably already have it too (part of librsvg2-bin, on which many popular packages depend)