Just because of the fact that a character is extremely powerful (for example, Superman) does not necessarily mean they are a bad character.
I bring superheroes up a lot on this forum, but a good example is the Flash. His whole thing is going fast, but he has to struggle with the dilemma of just not being fast enough, and the inability to save everyone. Yeah, he can time-travel, which he actually did before when he went back in time to the moment his mother was going to be murdered and saved her, which inadvertently resulted in an alteration of events that turns the entire world into a living Orwellian, dark, and murderous dystopia. He obviously does revert the timeline to normal again at the very end, but nonetheless does not ever time travel thereafter.
Give em’ trauma! I’m not talking about that ‘my dog died, boo hoo’ type of trauma, I mean Berserk-level trauma that’ll mess you up for days . Easiest way for character development
so a mary sue is someone who is friends with everyone, super perfect, no flaws, gets everything right.
an anti sue is the complete opposite of that, they are horrible, detestable, terrible characters that cannot do anything good, they are insufferably mean and spiteful and have next to no redeeming qualities
I wouldn’t call the the opposite of a mary sue, IMO the opposite of a mary sue would be a character that’s extremely weak or flawed. However, I find that these characters typically have great potential because starting at the bottom means they have a lot of room for growth. People love an underdog or zero to hero story, after all.
The type of irredeemable character you described isn’t really any kind of archetype, it’s just a poorly written character