Yeah, the first few pickups indeed make or break the run. There are some crazy powerful combinations and I kinda like it that way even though some of them outright break the game and trivialize the difficulty. But I don't like how it could introduce a "loot 1st chest & restart" tactic. Been thinking of a way to discourage that kinda like in Slay the Spire where you get a better start if you've reached the first boss on your last run. Slay the Spire is by the way the biggest source of inspiration on this game as it was the roguelite I was playing the most around the time I started the development on this. Never really played Dicey Dungeons (yet, on my todo list, love other Terry's games) but I can see the similarities.
The flame sword, crossbow and the hammer/apron are all very potent starting items with some powerful and well scaling interactions. I don't really hate that the different characters have kinda different difficulties but maybe the other two should be nudged closer to these power levels.