The definition of "Real Time" is
Real-time programs must guarantee response within specified time constraints, often referred to as "deadlines".
- Wiki
This means RTC sends messages which have to arrive in a certain time-frame to be called real-time. As far as I know, the time limit for RTC is a soft limit, meaning there is no number of milliseconds.
If you want to do RTC, or any network communication at all, be careful with what you send, keep traffic to a minimum (especially when your users might be on mobile). Sending hundreds of requests is a bad idea. You could improve on that by using WebRTC or WebSockets, so you have a socket connection instead of lots of requests. Even then, sending over a lot of data will still be a lot of data. Only send what you really need! You do not have to enforce Mutation Observers. You really should select the best tool for the job! And then there still is the issue of what you send. You should always prefer small binary over text-based protocols when on the wire. You could use something like pson to achieve that.