If you do this conversion more than twice a month, stop searching for a "free" solution. Buy X2Pro or switch your entire workflow to DaVinci Resolve permanently. The time you waste troubleshooting broken XML conversions is worth more than the software cost.
Blackmagic Design’s is the undisputed king of free conversion tools. While it is a full video editor, it acts as the best FCPXML to XML translator on the market. Fcpxml To Xml Converter Free
You have successfully converted your modern FCPXML into a legacy FCP7 XML file, which is readable by Adobe Premiere Pro, After Effects, and Audition. If you do this conversion more than twice