I'd get rid of the mechanic of getting unnecessary doubles. Specifically with randomized drops/rewards. I play Animal Crossing as a part of my daily ritual sometimes. I'd check for new recipes, get duplicates, and stop playing for the day. It's just not fun to reduce a game to work like that.
I don't think that there shouldn't be any chance or grind involved, but I think an invisible coding quirk that makes a new or desired item inevitably drop would go to reduce some stress.
I think sometimes grinds like that can really mess up people who can just dive into games or have that compulsive desire to get 100% completion.
Honestly, I kinda like that, but I think it would be rough to implement in a tabletop RPG due to the math involved. The math being X/(X+100) damage reduction.