I confirmed the crash... this should be reported as a bug, as a message "Invalid XML File" should be displayed, rather than a crash and loss of work.
You cannot edit the XML file in Excel, however, as Excel will not save the same format of XML file as used by ArchiCAD. (XML is more of a syntax than a format...so one cannot expect one XML application to read a file written by another.)
You can edit the XML file in a word processor or a dedicated XML editor, however. As long as you maintain the Graphisoft syntax found in the saved file, the modified file should load without problem.
One of the forum moderators
AC 26 USA and earlier • macOS Ventura 13.4, MacBook Pro M2 Max 12CPU/30GPU cores, 32GB