It does matter. For real-time the person will likely need a custom solution. That means coding the entire server in C++ or some other zero cost language with cu

It does matter. For real-time the person will likely need a custom solution. That means coding the entire server in C++ or some other zero cost language with custom protocols. For the non-real-time, it means using a pre-existing backend server. Many backend engineers don't know how to write a custom real time server from scratch. It's two completely different levels of skill. If you are hiring for this role and put out of job ad for typical backend engineers you won't get the right people for the role because, again, backend engineers typically don't have this skill.