Most of the time when I have an issue with @font-face is because my src path isn’t right. Maybe check the console to see if the call to your fonts files return a 404.
If your font-face is being called in the style.css in the root of your theme then your font path is more likely to be as follow:
url('./fonts/roboto-v30-latin-100.woff2') format('woff2')
../ means you go one back to the parent folder where ./ will look at the folder /fonts in your theme folder
@font-face being a css rule I don’t think the function you commented out would have anything to do with the fonts not loading.