Just rent a nice French bomb, and blow up Mar-a-Lago

Outside of the White House and Capitol (and maybe adjoining buildings) I would not want to do too much damage to the rest of Washington DC, as I think we could find lots of allies there.

Florida, on the other hand…

Make a documentary about time travel. Start by describing the different approaches used in various popular movies and TV series (always using Primer or Tenet as a punchline about an approach nobody understands) but gradually have the focus shifting towards the consequences of time travel, and then progressing towards the realization that actions have consequences even without time travel.

All while keeping with your premise of using the stars of time travel movies as the main talking heads in that documentary, instead of using scientists (though by all means use scientists as consultants throughout!)