It is targeted to the PHP community, not the language, it has no dependency on that, it is written in go and is based on caddy. (I’ve contributed with one PR in my former job)
It's really not. Not properly anyway. You'd spend a week, probably, just getting all the synchronization stuff right. Unless of course, you don't care about losing messages during a disconnection. Or you could just install this in a couple of hours and be done with it; not have to worry about security, maintaining NIH libraries, etc.
It is very easy, I have used it on various projects including chats, live dynamic dash boards, prompters and games. The SSE setup took less than a day, never had issues with sync. Never lost messages during disconnection or any issues.
I don’t know how you’ve been using SSE, but if you’ve had all these issues you must have been doing something very wrong.