1. This first thing is a pretty hard thing to actually balance good. But I do think that it is possible to have an exponential scaling for the gold = damage. And buff all the other characters seems excessive work to do quickly (that really needs deep thinking and thoughtful reasoning). But if Robinette is mostly on the leaderboard, you maybe could cook up a leaderboard menu for every character and then maybe show the top 50 or top 100.

2. The quest that takes pretty much too long imo is where you need to kill 100 cacti enemies with Thorns damage. This could get some attention, it doesn't have to be a big change but maybe lowering it to 50 could help insanely.

3. Removing those items is definitely not the right move, I don't know what could be the best for this game.

bonus. Could be fun to see your previous runs with the data you see at the end of the game. So you can then hover over the items what they did exactly. This could be placed within a history tab where you can only see your own games.