He’s in container 4261.
The search for the super soldier serum brings Sam, Bucky, Zemo and Sharon to a container yard at the port of Madripoor, where they find a hidden room containing Dr. Nagel.
When Marvel Studios needs containers, and a lot of them, there’s only one place to go. That’s the OFS Fitel backlot in Norcross, GA. This location uses many containers to erect green screen backdrops for outdoor shooting of large sets. Other MCU films like Captain America: The Winter Soldier and Black Panther have shot sequences in this “studio” environment. As Zemo drives away, some of the blue paint seen in the satellite view is visible on the tarmac.
(The Falcon and The Winter Soldier S01E03, 2021)