What tech to use when you are just starting

In the beginning, you are trying to find out if there is a need for your app, which means you personally have to find people to try your app. Since there is no marketing, there is no sudden spike in traffic you have to think about. Therefore, you should aim for quick prototyping instead of scalable solutions. Here is a list with the complex option in the first column and simpler option in the second:

#	complex	simple
1	Mobile app	Progressive Web App
2	MySQL/PostgreSQL	SQLite
3	Queue worker	defer()
4	Broadcast with events	Echo whisper
5	Mailgun	PHPMailer + gmail
6	ElasticSearch	SQL queries

The simpler options also use less resources which means that you can host your app on a cheap VPS for 10$/month.