First, you are assuming that you will every be aware.
While it is entirely within the realm of possibility that you could hide fudging forever, I have never seen anyone do it. And it would be kind of creepy to be playing every week with someone who lied to you.
Second, unless you know HOW the DM fudges, you don't know any such thing.
Incorrect: any fudging in any direction means my decisions matter less.
So now something that I've never done in my life is a habit? What nonsense are you going to tell me next? I can't wait.
I don't understand. In your example: a fictional GM is fudging (we are using "you" as verbal shorthand for the example). I am telling you the consequences of that. None of this has anything to do with your biography.
Extreme bad luck has nothing to do with your actions. Sorry.
It completely does: choosing to play D&D means choosing to play a game where fights might happen and you might take x damage from y spell and z chance of failing a save etc. The extreme bad luck result is part of the rules of the game.
There ARE games where extreme bad luck cannot result in death. Or house rules that can mitigate it (allowing 1 reroll per game, for instance). If I have chosen not to play one of those games or not to play with said house rules then I have 100% chosen to play in a game where extreme bad luck can kill me (or do all kinds of other things I may or may not want in the sort term). If I didn't want that, I would be playing a different game.
I have chosen, as a player, a level of caution equal to the 1 in 20 chance of a crit (or whatever the chance in the system is).
Taking a monster's Natural 20 away from me is negating my choice to play a risky game.