The lead in the movie discovers he’s the replacement for a secret world guardian who monitors all activity in the world. I never saw the end but I remember seeing the control room with dozens of TVs showing world activity. I’d like to see the whole movie but I don’t know the title or the actors.
In searching on Google, I found The Adjustment Bureau starring Matt Damon. I will keep looking. Please let me know if this is it. The movie you are looking for sounds like a great story line.
https://en.wikipedia.org/wiki/The_Adjustment_Bureau
I’m also thinking it might be Counterpart. Not a movie though. It’s a series.
https://www.imdb.com/title/tt4643084/?ref_=nm_flmg_act_36
You haven’t specified a year, or a range of years, but your description reminded me of an old movie called ‘The Questor Tapes’ from 1974. Without giving spoilers, since you didn’t see the ending, the protagonist is just as you have described, being tasked with monitoring the whole world. You can look up that title on IMDB (or wherever else you choose). The only source I can find that has somewhat of a movie trailer is linked here – it shows a brief glimpse of a control room with TV’s that he’s monitoring: https://www.youtube.com/watch?v=q0dmypfBYvE