The logline isn’t that bad, I would just focus it down a little more

for instance, since we are talking prom, you do not to tell us the lead is a teen.

Here is an attempt to say the same thing you said but with less words:
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“To win the head cheerleader, a prodigy with zero social skills hires a popular but dumb-as-a-rock football star to teach him how to attract his crush in time for the prom.”
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Hope that helped

While it might seems like entering the virtual world is what set’s the story in motion,
since the goal of the story is stopping the demon king,
The inciting incident would be when the lead releases the monster.

I am going to do a logline attempt, I am also going to try to personalize the quest as a result your logline will differ:
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“When he accidentally releases the demon king while trying to Illegally hack the game, a disgraced gamer and his guild mates must defeat the virtual monster if he is to atone for his mistake”
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If this has not been written, here would be a few thoughts on how the story line could go:

1: At the beginning of the story the lead is a bit selfish, He hears about this uber weapon and he tries to hack the game to get it.
2: The devs play this cruel trick, anyone hacking the sword will release the demon which will ravish the world
3: He becomes a disgrace to his fellow gamers and is only accepted among a guild of losers.
4: Together they go on a quest to gather ingredients for a super spell
5: The guild has to work together to solve problems and as a result the lead is forsed to lose his selfishness and learns to be a team player
6: in the end they defeat the demon
7: and he is rewarded the sword he tried to hack, but now he has earned it.
8: He is a hero instead of a disgrace.

The End

hope that helped