Ehrm, I don't want to sound rude or anything, but like in dark souls being frustrated is kinda part of the gameplay experience.
It usually pushes you further in literally gitting gud.
Depends on the person, ofc. I don't know if there's a save editor for it, but it should suffice with changing the toon armor to a well built, mixed attack/defense set of end of high rank armor and your favourite weapon flavor (also end of high rank level, it should be arround PH8 or PH9).
This should allow to speedrun the low rank very very easily and becoming increasingly more hard (And fun!) to the end of high rank. At the end of certain quests of high rank, the offline game ends. G rank is "only" for online play (there's some offline quests, but need online play to unlock).