Not sure if it's just me behind a draconian firewall but Neo-Grotesque doesn't load Inter for me, even though it's on Google Fonts. Why not download it from there?
The site doesn't load any webfonts. It only attempts to use already-installed "default" fonts from various systems. The GitHub readme[1] says Inter is a "user-installed" font, so I'm not really sure it should count here.
1: https://github.com/system-fonts/modern-font-stacks#neo-grote...