Weaver Xtreme PLus does not have a shortcode that uses “[widget id=’abc’].
At some point, Weaver started to recommend a plugin called Widget Shortcode (https://wordpress.org/plugins/widget-shortcode/) that would use that syntax.
It seems that that plugin does not seem to be maintained any longer, even though it has 90,000+ active installations.
But at any rate, the id field of that plugin shortcode uses a name generated by WordPress automatically, or a name provided by the content creator. It is a manual process.
I’m not sure what we might be able to do to help with your situation, but a link to the site might be useful, but I don’t think this is a theme or Xtreme Plus issue.