If your icons are purely decorative, you’ll need to manually add an aria-hidden attribute to each of your icons so they’re accessible.
In the case of focusable interactive elements, add the aria-label attribute.
If your icons have semantic meaning and are not focused, you’ll need to manually add a few things so that your icon is appropriately accessible:
aria-hidden attribute.
Provide a text alternative inside a (or similar) element. Also include appropriate CSS to visually hide the element while keeping it accessible to assisitive technologies.
title attribute on the icon to provide a tooltip for sighted mouse users.
See https://fontawesome.com/how-to-use/on-the-web/other-topics/accessibility
I'm not sure we have any in the third category.