Workaround for DB connection issue in upgrading to Drupal 9.4.x

Cannot instantiate abstract class Drupal\Core\Database\Schema in
 Drupal\Core\Database\Connection->schema()

$class_loader->addPsr4('Drupal\\mysql\\', 'core/modules/mysql/src/');

// Acquia include settings.
if (file_exists('/var/www/site-php')) {
  // Acquia require line
  require '/var/www/site-php/XXX/XXX-settings.inc';
}

// Acquia include settings.
if (file_exists('/var/www/site-php')) {
  // Workaround for database error
  $class_loader->addPsr4('Drupal\\mysql\\', 'core/modules/mysql/src/');
  // Acquia require line
  require '/var/www/site-php/XXX/XXX-settings.inc';
}