Deprecated function: Return type of Drupal\google_analytics\Component\Render\GoogleAnalyticsJavaScriptSnippet::jsonSerialize() should either be compatible with JsonSerializable::jsonSerialize():

By experiencing the same issue with external_link_popup module which has been fixed the same as per comment #8 by joelpittet, attached patch adds the missing #[ReturnTypeWillChange] statement.

The patch in #10 is how it was fixed in 🐛 Deprecated function: Return type of Drupal\google_analytics\Component\Render\GoogleAnalyticsJavaScriptSnippet::jsonSerialize() should either be compatible with JsonSerializable::jsonSerialize(): mixed, or the #[\ReturnTypeWillChange] attribute should be u Fixed for google_analytics 4.x (commit b703904).

With the sunset of legacy google analytics, the 8.x-3.x module is now unsupported. If this is still an issue with the 4.x version, please file a new issue in the queue.