Beerus would probably win. He is a god of destruction in the Dragon Ball universe. His power levels are off the charts compared to Naruto. He can destroy planets with a snap of his fingers, and his combat skills are far beyond what Naruto has been shown to be capable of in the Naruto universe.
In the 'beerus vs omega shenron fanfic', Beerus would likely start the fight with his confident and somewhat arrogant attitude. He might underestimate Omega Shenron at first. However, Omega Shenron's ability to absorb energy could give him an edge. If Beerus doesn't quickly realize the threat and use his full power, he could be in trouble. But ultimately, Beerus' experience as a God of Destruction might give him the upper hand in this fictional battle.
One possible plotline could be that Broly, in his rage, accidentally provokes Beerus. Broly, not knowing who Beerus is, attacks him. Beerus, initially amused, decides to teach Broly a lesson but soon realizes that Broly's power is growing at an alarming rate. This leads to an intense battle where Broly pushes Beerus to use his full power. Another plotline could be that Beerus hears about Broly's power and decides to test him. He travels to Broly's location and challenges him. Broly, seeing Beerus as a threat to his friends or his planet, fights back with all his might.
In a 'Goku vs Beerus' fanfiction, it's really hard to say who would win. It could depend on how the author wants to write it. If the author wants to show Goku's growth, Goku might win through some new transformation or power - up. But Beerus is a powerful God of Destruction, so he also has a great chance of winning.
Another theme could be the clash of different universes. Amazo is from the DC universe and Saitama is from One Punch Man. Fanfics might play around with how these two different universes' rules and powers interact when these two characters meet. Also, there could be themes related to respect and rivalry. Saitama is often very nonchalant about his power, while Amazo is a complex android with various abilities. How they view each other in the fanfic can create interesting storylines.
The power levels. Beerus is extremely powerful as a God of Destruction, and Omega Shenron is no pushover either. The clash of their powers is exciting to imagine.
There could be a storyline where Beerus, out of boredom, decides to train Goku Black instead of fighting him. But Goku Black misinterprets this as a sign of weakness and attacks Beerus. This could lead to a battle where Beerus has to hold back at first to avoid killing Goku Black, but as the fight progresses, he realizes he has to use his full power to subdue him.
One interesting concept could be the power struggle. Beerus is an extremely powerful deity in the Dragon Ball universe with god - like powers, while Naruto has his own set of formidable ninja abilities. In fanfiction, they might explore how Naruto's chakra and jutsu would fare against Beerus' energy blasts and hakai ability. Another concept could be the clash of their worlds. The ninja world of Naruto is very different from the Dragon Ball universe, so seeing how the two settings interact, like how Naruto's friends and village would react to Beerus' presence, can be really engaging.
Beerus would probably win. He has the status of a God of Destruction, which means he has a certain level of power and abilities that are unique. His Hakai ability can erase things from existence. Broly is strong, no doubt, but he is still a mortal (in a sense). Beerus has been shown to be far above most mortals in terms of combat ability and raw power. In a fanfic, unless the writer completely changes the power dynamics, Beerus has the edge.
Saitama would win. He has shown incredible strength with just one punch. His power seems limitless, and in a fanfiction scenario, his simplicity and raw power would likely overpower Jiren's more complex abilities.