fxg to ai conversion is typically searched for by users that own old graphics files in Adobe Flash XML format (.fxg) and are looking for a way to import these to Illustrator.
Since Flash had been discontinued and Illustrator dropped support for it (and thus FXG format), the only reliable way to achieve this is to find someone who still has old version (up to CS5) of Illustrator that can open/import .fxg files. There doesn't seem to exist any other viable alternative for this.
Updated: September 25, 2023