I don’t think it’s fair to call Slay the Spire (StS) a clone. While Card Quest introduced a lot of the key elements years earlier, StS adds enough innovation that it feels like a totally different game. Definitely would be more fair to say StS popularized a lot of the mechanics rather than invented/pioneered them though.
Haven’t played, but I found this (negative) review compelling: https://www.youtube.com/watch?v=QF-Kd2BBpx8
He did play through the whole game.