How can I improve this code to speed the sending of bulk push notifications?

await connection.query('SELECT subscription_json FROM notificationsubs ORDER BY id DESC')
.then(async (result) => { 
	for(let index in result){
			await webpush.sendNotification(JSON.parse(result[index].subscription_json), payload)
			.catch(async err=>{
				await connection.query('DELETE FROM notificationsubs WHERE subscription_json=?', [result[index].subscription_json])
		} catch(error){ console.log(error)}
console.log("Finished sending notifications")

It currently sends push notifications with the “web-push” npm package. Each notification is sent 1 by 1. I feel that this is inefficient. I heard that Google can receive a request containing 1000 notifications at a time. How can I modify this code to do that? I couldn’t find a clear way to bulk send push notifications using the web-push npm package.