Despite Goku and Vegeta's fame in Dragon Ball, author Akira Toriyama has pointed out that the strongest character in Dragon Ball is not one of these two.

With the introduction of Dragon Ball Super, new characters have surpassed Goku and Vegeta, pushing them to higher levels of power. For instance, Goku has Ultra Instinct, and Vegeta has Supreme Ego. However, in the end, Gohan still surpasses the development of his father, recently transforming into Gohan Beast.
The latest chapter of the Dragon Ball Super manga, adapted from the movie 'Dragon Ball Super: Super Hero,' revolves around Piccolo and Gohan facing off against the Red Ribbon Army. In this storyline, Gohan has reached a new level of power, unlocking the Beast transformation.

Beast is the strongest form Gohan can achieve, enabling him to completely dominate Cell Max, a monster created and upgraded from the data of Cell. This means that Cell Max has been improved and is much stronger than Cell. It's speculated that once perfected, even Broly wouldn't stand a chance.
In an interview, author Toriyama expressed the creator's belief in Gohan's superiority over all other characters. He stated, 'Gohan is stronger than anyone, but he never gets a chance to shine.' This statement from the author further proves that Gohan's strength surpasses Broly, Vegeta, and even his father, Goku.

In the climax of Dragon Ball Super: Super Hero, Gohan reveals his silver-haired form - Gohan Beast, witnessing the brutal battle of Cell Max against Piccolo. This unique and powerful form is entirely different from Goku or Vegeta's recent transformations. It's not the first time Gohan proves he's the strongest when needed.
In the manga, while facing Kefla, Gohan once stated that his goal is to evolve 'as an Earthling, not as a Saiyan.'
Indeed, the Beast state originates from the Potential Unlocking Capability after Gohan undergoes the Potential Unlocking ceremony with Elder Kaioshin. Gohan unleashed his hidden potential and achieved a supremely powerful form, surpassing even Super Saiyan.
Initially, Gohan was the main character of Dragon Ball Z, but fan favoritism and editors kept Goku in the spotlight. Since childhood, Gohan stood out, surpassing adversaries like Raditz, Frieza, and Cell. His ability to control his latent power impressed even Goku, leading him to entrust Gohan with the task of defeating Cell. The recent appearance of Gohan Beast once again asserts his position as the strongest.
Gohan Beast is predicted to play a significant role in future installments of Dragon Ball Super.