Kong: Skull Island still reigns supreme as the biggest box office hit the Monsterverse ever produced, yet six years later it still hasn't been given a sequel. Kong himself made a follow-up appearance in Godzilla vs. Kong, ultimately losing to the nuclear lizard before teaming up with Godzilla to stop the malevolent Mechagodzilla. Despite his defeat, Kong received much more backstory in Godzilla vs. Kong and ultimately had the stronger story of the two starring kaijus. In theory, Godzilla X Kong: The New Empire will elaborate on the background of both Titans.

https://screenrant.com/kong-2-movie-development-taking-long/