The current MonsterVerse timeline is now 5 movies and 2 TV shows deep as of Godzilla x Kong: The New Empire, but the history of this cinematic universe dates back further than some might realize. The legendary lineup of Toho creatures has been around since the 1950s. But it was in the 2010s that Warner Bros. and Legendary decided to redo this concept with the added help of today's VFX technology. Legendary's MonsterVerse timeline began in 2014 with Godzilla, which showed the first public display of Massive Unidentified Terrestrial Organisms — also known as MUTOs or Titans.
https://screenrant.com/monsterverse-timeline-explained-godzilla-kong-movies/