Why dora can beat goku, superman and one punch man First off, Dora has her map, which essentially gives her omnipotence; this is because it always knows the location of whatever she needs and would also know the location of her opponents, so if Dora fought Goku, the map could tell her to go to space. Not only that, we see the map operating in space, implying that Dora can survive in a vacuum.
Next, Dora has her backpack; with this, it could give whatever Dora needed to win the fight. Against Superman, she could pull out kryptonite, and against Goku it may give her the Dragon Balls to wish Goku away. Now, you may say this is a no limits fallacy, however in the backpack song it is explicitly stated that "anything you might need I got inside for you" so it can give Dora anything. Not only that, the backpack is a magically powered entity itself.
Finally, Dora wields the blue arrow; this may be one of the strongest weapons in fiction. This is because the arrow does whatever she tells it to do, and since it is controlled indirectly by the player of Dora's game, it is at least outerversal+, giving it more than enough strength to restrain Goku or Superman. In fact, the arrow is so powerful that it can literally change the plot and refuse demands from the viewer, meaning it can defeat beings such as the One Above All since compared to Dora us the viewers are the One Above All, yet Dora can still make the arrow ignore us, meaning it can literally defeat omnipotence. At bare minimum the arrow is capable of mind control on a beyond omnipotent level, since it made swiper stop swiping, so she could make any of her combatants off themselves.
Dora also has various skills from her many adventures, from learning how to drive to knowing how to pilot an airplane, indicating that she herself has super intelligence. Dora picks up any skills she needs. Dora could also summon the wishing stars, which would allow her to do anything she wants.