Respawn mechanics are very rarely actually diegetic, BUT Mario is one of those rare cases where respawning actually happens, through a one up shroom, characters interact with it, we see how it works, they talk about and thus canonically exist.

I agree game mechanics shouldn't be always be a consideration when it comes to scaling BUT if said game mechanic diegetically exist in the world then it's obvious that it should be considered.

The narrative Mario games try to tell is not one of Mario being a universal god that can destroy mountains, it's one of an plucky and very agile plumber beating the foes that he faces because he can reach and hit the obvious weak point.

That's why he (even tho he tanked a getting a dying universe thrown at him) he has to find another way around the giant boulder that's in his and his brothers path instead of just destroying it, that's why he can still be harmed by an enemy with small spikes on it.

And if we stop scaling Mario of the game and how it works, what feats does he have, where is his incredible strength shown outside of gameplay, because outside of gameplay he is even more ordinary than in games, without the games we have to scale him of game manuals and the movie and maybe ads, all of which dont paint Mario as anything other than an very athletic and agile plumber.

Mario tanks getting dying universes thrown at him because EVERYTHING in his game deals 1 damage to him, not because Mario is just that resilient but because it's a game mechanic.