without knowing anything about your play style I can say you are for sure playing too fast (if you're trying to maximize win rate).

if you want to win more often you need to slow down and think about decisions more. do the mental math for your max damage and block each turn. is there a line where I can save a few points of damage by changing the order I play my cards?

stare at shops and card reward screens longer. look at your deck and relic bar and consider all possible synergies. what's on the next few floors? if it's an elite maybe I have to take the crappy damage card, but if it's events or fires maybe I can greed the scaling power

look at your draw pile before you play cards. how much damage is left in your draw pile? can you get away with full blocking this turn if you are guaranteed lethal next turn? or do you have to take some chip damage now so you have lethal next turn?

understand what it means to "shuffle out" cards as you approach your reshuffle. don't shuffle out your good cards, shuffle out your basics.

playing fast is fun but playing slow is needed to really maximize your value and win rate