Grand diplomacy is actually the responsibility of the incumbent US government, i.e. Joe Biden. But that doesn't interest his designated successor. Donald Trump is already very active on the world stage.
The former and future US president still lives in the south of Florida, but his return to Washington is imminent. However, no one would be surprised if Donald Trump had already moved into the White House. The official transfer of power will take place on January 20, 2025, and the stands are in place for the ceremony. But Trump speaks as if Joe Biden and Kamala Harris were already gone.