Also a big fan of Slay the Spire, I have about 200 hours in it. Another game I'd recommend is One Step From Eden, a hybrid deckbuilder and roguelike similar in a way to StS, but with a much more involved style of gameplay.

I find that it feels just as challenging (and satisfying) at my current ascension of 18 as it felt when I struggled to complete a run pre-ascension. Which is a remarkable achievement in game design.

I do wonder if me getting bored with it will occur at Ascension 20, Ascension 20 with Heart, or sooner.