"Wakanda Forever" seems at least partially engineered as a rebuttal to those who read the first "Black Panther" as being uncomfortably friendly to the CIA.
Yes, while Namor might be the film's central antagonist and commit some genuinely upsetting acts of violence, the actual villains of the film are the political forces that have pitted Talokan and Wakanda against each other.
The United States is now actively seeking out Vibranium, and Talokan is ready to defend itself via acts of aggression that inevitably get blamed on Wakanda. Like Wakanda, Talokan is powered by Vibranium and has kept itself secret from the rest of the world, but its secrecy is threatened now that Wakanda has revealed itself to the world.
Instead of Atlantis, he's the king of Talokan, a nation shown in flashback to have been founded by Mayans escaping genocide (much more tastefully handled than the conquistador flashback in "Eternals"). Namor in this film is a fascinating character and an intimidating threat.