I don't know how it will help but Krita use svg import and krita is also available on all platforms.
I'm involved in a project written in Rust, called IconPie (1). It's a command-line tool to generate application icons from raster graphics or vector graphics images.
I'm pretty sure IconPie has a great potential to suit your needs and I'm willing to help adapt the tool to suit your needs.
Would you please join the discussion here (2) ?