Mustache vs Symfony

I'm about to begin working on an API, for which I plan to add GraphQL connectivity for processing data. The data processed will mainly be audio files being downloaded/uploaded with some user messaging & authentication.

I don't mind the difficulty in any service since I've used C++ (for data structures & algorithms at least) and would also say I am patient and can learn fairly quickly. My main concerns would be their performance, libraries/community, and job marketability.

Why I'm stuck between these three...

Symfony: I've programmed in PHP for back-end in a previous internship and may do so again in a few months.

Node.js: It's newer than PHP, and it's JavaScript where my front-end stack will be React and (likely) React Native.

Golang: It's newer than PHP, I've heard of its good performance, and it would be nice to learn a new (growing) language.

In my humble opinion the best available php platform is "API Platform". I have tried a lot of backend frameworks in the last 10 years, and that is one of the best, at least in the PHP ecosystem. It's based on Symfony, it supports plenty of features like Swagger docs, Rest API, GraphQL. You can plugin React Admin to have a full admin in no time. But the best part in my opinion it's how you can easily extend the backend taking advantage of the ORM Doctrine (which is one of the most mature available across all technologies) and all the plugins of Symfony. The fact that the Doctrine entities are in automatic relation and they can be exposed as GraphQL it's a big win if you have a complex database. It is also possible to reverse engineering an existing database and create automatically all the entities, admin, restapi, graphql endpoints ... welcome to the future :)