Does the monitor that a streamer see's look different than what they stream to their viewers?

I don't really understand how the relationship between what a streamer sees vs what a viewer sees when it comes to hardware and content. If I have a 1080x1920 monitor and is 140hz does that mean the viewer see's the exact same thing i see on my screen? but then how does fps play a role in that because there's a limit on bitrate? idk all the technical jargon is very difficult for me to understand. i know i could just press enhanced broadcasting and call it a day but i like to kinda know the behind the scenes stuff. idk it's cool 2 me