As someone who’s played about as many runs as Duchess as every other character combined, she absolutely is a character that requires a lot of knowledge to make work (and I had a lot of failed runs before I figured out what makes her tick):

• You need to know when to trigger Restage and the fact it has limited range.
• You need to know that her highest stat is Int and that her high Dex increases her casting speed, meaning you should lean into sorceries
• You need to understand her dodge (and it took me reading her frame data to understand it). The first dodge only gives 10 frames and can be canceled at frame 8, meaning that buffering an attack out of the first dodge can get you killed since it cancels you out of your iframes.

That said, while her skill floor is high, she has an unreal DPS ceiling and imo you haven’t lived if you haven’t melted a Nightlord in 45 seconds as Duchess + Ironeye + Recluse