// get all possible element ids
$sectionId = X;
$query = (new Query())
    ->select('elements.id')
    ->from('{{%elements}}')
    ->leftJoin('{{%elements_sites}}', 'elements_sites.elementId = elements.id')
    ->leftJoin('{{%entries}}', 'entries.id = elements.id')
    ->where(new OrCondition([
        ['=', 'entries.sectionId', $sectionId], <-- your section Id
        ['is', 'entries.sectionId', null],
    ]))
    ->andWhere(new OrCondition([
        ['=', 'elements.type', craftelementsEntry::class],
        ['=', 'elements.type', YourCalenderClassComesHere],
    ]))
    ->andWhere(['elements_sites.siteId' => 1])
    ->limit(10)
    ->offset(0)
    ->column();

// populate entry by Id
foreach ($query as $elementId){
    $element = Craft::$app->getElements()->getElementById($elementId);
}