I hear you: I don't like how skinny the letterforms are. There's an "extended" variant that I find much more pleasing. I put together a customization you can see here: https://codeberg.org/ashton314/iosevka-output (there's a nice screenshot on that page).

You can probably get the proportions you want if you find a way to tweak the line spacing (also possible by adjusting the `leading` option in `private-build-plans.toml` and rebuilding).