Hi

I am new here . . . but for backend - I assume you implement it with NodeJS - maybe you could give try to FeathersJS Server? I have used it previously for my PHD project. It comes with support of dozens of databases. You do not need to worry about database scripts and connection routines, FeathersJS abstracts all of this for you. It implements connection with database using services. These services conform with CRUD philosophy which obviously you can customize based on your needs.

This server is well documented.

Also authors of this server claim that you will be able to deliver production grade app within days and from my experience I can say that this is true. This server should be good choice for beginner

Good luck!