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.
This is weird but I would remake most RPG stat systems to have logarithmic diminishing returns. For instance 100 resistance halves damage, 200 cuts out 66%. No more hidden softcaps, I'm looking at you FROM!!!!!!!!! This is easier from the standpoint of balancing loot and all that IMHO, because 200% increased damage in item form is negated by 200 resistance.
Armor in MOBAs works this way because it worked that way in Warcraft 3 and everyone just copied it. 100 armor effectively means that your health bar is 100% larger vs physical damage, aka 50% damage reduction. 200 armor is 66.6%, 300 is 75%, etc.
You see other kinds of "natural soft caps" in stats like "reload speed" or "cooldown rate," since if you get 1000% that doesn't mean "instant," it just means "11x as fast"
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.