After the betrayal you are left with a deep trauma and vengeful spirit. You curse your own lack of power and fate, but in this dark hour you also find determination to continue on to not let those bastards who almost killed you get away with things.
You find out that your power/job isn't useless and you find new applications for it. Unlike those other showoffs and immature fools your power can make use of your creativity and cleverness. The others had powers that seemed very generic and high in aesthetics, but you found that your power was far more versatile.
There was some lingering rage towards the fact that you didn't get a flashy and impressive power, but you no longer care that much. You find that what truly matters is not the power, but the will and intent to use any resources at your disposal to accomplish your goals and look out for yourself.
Well, that's the character that you are to me. You make jokes and hope that you will be some kind of ultra-talented loli with an amazing power, but things completely turn out differently.
Meanwhile, I the class president am trying to teach these f***ing little shits attempted murder is wrong.
Somehow my class/ability ended up being labour/farming intensive and I actually only have utility as support for the most part. At the best of times I have an inexhaustible amount of raw power that is not very versatile in actual combat because it is too predictable and has too many weaknesses/drawbacks.
Standard black haired light novel guy who got back stabbed and then becomes super edgy. His hair grows white and he gets lots of waifus for no excplicable reasons besides him the protagonist.
I don't think you are actually backstabby. There are people who are genuinely naturally bad and arrogant who would have the advantage at the beginning with their straightforwardly/conventionally powerful abilities versus your utility ability/class that you haven't found or created an effective way to utilize yet.
Meanwhile, the whole time, I will be thinking, "I'm trapped in a sea of idiots. These kids are completely into their power and themselves. The endless praise they get for their abilities and the way they have already caved into the pressure of expectations placed upon them is gravely disappointing. The royalty that summoned us can't be trusted. This is hell."
Wow who knew people could get Isekai'd then slapped onto the plot of Arifureta in the short span of time I was gone. I'm going to hope you people didn't steal my barrels and barrels of cider out of my Hogwarts van while I poofed into smoke for a while.