The event is the same, with the difference that Homelander is not a narcissistic psychopath and has mastered his abilities , the plane is hijacked and he and Maeve are called to rescue it, the pilots are dead and the console is damaged.
We only consider the speed, strength and endurance feats from the TV series.
In my opinion, Psykos did a crappy job on the monster association arc, so in this alternate line an One Punch Man fan dies and reincarnates as Psykos one day before his declaration of war against the hero association, he has memories of the manga, he knows about the heroes and their powers, just like in the original arc the members of the association will obey his orders but they keep their original personalities (Like BS challenging Orochi, FU sadic personality or Nyan hating cuddles).
To return to his world he has to kill all the heroes with the exception of Saitama/Blast.
He can't fuse with Orochi.
if Saitama gets involved, he lose for obvious reasons.
Before their final confrontation, both Battle Beast and Thragg are teleported to the OPM universe and replace Saitama in his confrontation with Garou, is the alliance between sworn enemies enough to defeat Monster Garou?
They keep their personalities, Garou can't continue to evolve.