the only way i think durr or anyone else in his position would have a chance is to make it blitz, and hope that the GM you're playing is a blitz fish
This is completely backwards. You're up a rook. The major way a typical club player would lose in that situation is to blunder. Playing blitz massively increases the chances of you blundering. I'd want it to be a correspondence game, if possible.
I think people are overestimating how difficult it is to win up a rook. Grandmasters are not magical. They can't change the fact of what is on the board. I would be a favourite against Garry Kasparov if he played down a rook. The basic gameplan is trade off as many pieces as possible, open some files so the rook is useful, and keep the king safe.
Contrast that with what durrr did (I've taken a look at the games now). In game 1 he failed to develop, instead playing the crazy Qa5 and stuffing his queen down on a3 in some attempted pawn-grab, when he's already a rook up. He allowed his king to be trapped in the center and broadly speaking that's why he lost. In game 2 he actually twice runs away from piece trades, retreating his bishop to e6 and then d7 when a trade with the knight is possible. The losing move in this game was d4 in response to curtains' e4. It not only closed up the center, reducing the power of his extra rook, but it locked all his pieces away from the K-side, where curtains is about to attack. Look at the board after ... c5 and notice how utterly locked out of the K-side durrr's queen is. It's going to take him like 4 moves to get her there if he needs to.
Plenty of Masters/GM have gone to Central Park and got owned playing speed chess. If youre reasonably good at speed chess ,this would def be the way to go IMO. Much easier to trade down in Blitz. And I certainly dont want to play a master in a game where he has time to think more than a handful of moves ahead.
And you would def not be a fav over Kasparov down a rook. Hes going to mate you long before that rook comes in to play.