For backend, most languages are acceptable, and depends on your team and personal preference.

Python will do the job. Java-shops still chug along. Go-lang is nice. Node-js is fine.

Personally, I prefer javascript to GO, as it is more expressive language, and because you have it server-side, you dodge most of its browser-side warts.

But if you plan to run in the Kubernetes ecosystem, Go has some nice things, and is usually simple and has the 'one obvious way to do it' vibe.

I used both GO and Node 'in anger', and one was not obviously better than the other.