The toxicity of questing in MMORPGs today

[Atoli]

it's something that sets you apart from the world and helps you feel a hero.

Nothing ever will set you apart from everyone else unless the entire game was made entirely only for you.

Currently, most of my friends are playing the 20 year edition of Rise of the Tomb Raider. It's a single player game, but of course we talk about it.
Going by your logic, going up against Trinity, uncovering all these secrets, etc. is not worth anything, because the others are doing the same.
But you might argue that it doesn't count because Lara is a properly established character, not a blank slate like the WoL.

Well, then let's look at other games that have fairly blank slates; since the article has nostalgia written all over it, how about Pokemon Red/Blue?
As a child/teenager, when you finally beat the Pokemon League, or completed the Pokedex and exitedly told your friends in school,
did it also take away from your enjoyment that they had also beaten the PL or saved the world from Team Rocket?
I assume not. Why should that be different in MMOs? You know the other players are real people too, so why does it bother you that other real players go through the same story and finish the same achievements?

In YOUR version of the story, YOU are the hero.
The game might aknowledge that others are there and helped you, but you are the only one in YOUR perspective who is special.
Just how YOU were the new champ in your copy of Red/Blue and your friend was in his
I do not see any reason why others having the same story is detrimental to your own experience other than robbing you of a fake sense of being better than others in real life, which is just sad, if you actually need that feeling to enjoy a game.
If you want to be proud of actual non-made up achievements, then beat extra hard fights that are not part of the story but show your actual superior ability to play the game well (in this case, savage mode, I guess?).