No, the 1954 Godzilla movie was one of Godzilla's earliest works, but it was not the earliest. The name Godzilla first appeared in a Japanese manga of the same name in 1942. Before that, there were other forms of Godzilla's image, such as appearing in news reports, posters, and advertisements.
Godzilla was a famous Japanese monster that appeared in many movies and games. The following are the names of the movies where Godzilla fights other versions of monsters:
1 Godzilla: King of Monsters (2004) -Godzilla's debut movie was produced and distributed in Japan.
Godzilla 2: Monster Island (2014) -This movie is a continuation of Godzilla, produced and distributed in Japan.
Godzilla: Monster Planet (2017) -This movie is a derivative work of Godzilla, produced and distributed in Canada.
Godzilla: Rise of Darkness (2020) -This movie is a remake of Godzilla, produced and distributed in Japan and Canada.
Godzilla: Rise with the Sun (2019) -This film is Godzilla's international collaboration, produced and distributed in many countries.
Godzilla: Wolverine (2020) -This movie is a superhero movie about the battle between Godzilla and Wolverine.
Godzilla: Spirited Away (2010) -This movie is an animated film by Godzilla, produced and distributed in Japan.
8 Godzilla: Monsters Power Corporation (2015) -This movie is an animated film by Godzilla, produced and distributed in Japan and Canada.
Godzilla: The Big Movie 2 (2018) -This is the second film in a series that was produced and distributed in Japan.
Godzilla: Monster House (2005) -This movie tells the story of Godzilla in a house. It was produced and distributed in Japan.
In the prehistoric novels, saints were divided into many levels, including Innate Saints, Primordial Saints, Asura Saints, Chaos Saints, and so on. Every saint had their own special abilities and status. For example, Su Hao in " I Am the Guardian God of the Human World " attained the Sage Throne three times and became a Saint of the Three Sage Thrones, while Xuan San in " I Am a Refinement Stage Saint " attained the Sage Thrones of Heaven, Earth, and Man through different identities. Then, through the practice of crossing the heavens, he achieved the highest of the heavens. In short, in the Primordial World, becoming a saint was the ultimate pursuit and dream of every immortal cultivator. I hope you like my recommendation.
Godzilla Earth is not a fanfic. It has its own official production and creative process, distinct from fan-created works. It's a legitimate entry in the Godzilla canon.