The rule of underdogs and unexpected(?) plot twists dictates that they should all be there to assassinate the original protagonist.
BUT they do not know that their miniscule(?) changes to the timeline killed his nanny which caused him to venture out and grow prematurely. He is now surprisingly(?) more OP than before.
Regressor's instant kill attack fails to end him while a misunderstanding between reincarnator and transmigrator causes them to bicker for five chapters.
Transmigrator's unexpected behavior confuses regressor and they start wondering if their memories of regressing could not be wrong...
Finally, reincarnator uses their knowledge of both a native and a former outsider to resolve the conflict and they unleash their strongest attacks on our protagonist... Or that's what they think! When he crumbles to dust they realize he escaped three chapters ago.
As the story progresses, reincarnator stops focusing on the plot and goes off on a cooking adventure with their adopted children.
Regressor accepts that our protagonist has changed forever. His early progression enabled him to save his long-lost sister and gave him something to protect. Regressor is sure that protagonist will not destroy the world during his fight with the great evil™ this time.
Transmigrator refuses to accept reality. "But what about the plot?" quickly turns into their catchphrase. Finally, they fight our protagonist to correct the story, but, depending on the tags, realize they have been in love with protagonist for a long time or end up getting brutally murdered.
While we are drowned in teasers for the eventual showdown with the great evil™ the novel slips into an obligatory three book period of slightly off-canon slice of life, badly executed undercover or amnesia plot lines, and brain-rotting romance mixed with some face slapping.
Beautiful.
Alternatively, we experience the great loop. Did you know that another batch of three extraordinaries just appeared? Our powerful protagonist is sitting in yet another bar experiencing yet the same thing. What, they are too powerful? Protagonist flees for the time being, he will be back. Repeat.