Ahahah thank you so much for your awesome and tasty comment!
You are absolutely right about the endgame, I also spent wayyyy too long finding my last mythic! I wanted to add a feature to increase the chance of finding a new (not owned) card each time you open a "failed" booster, but I wouldnt have enough time to test it and was scared to mess up the droprate ^^
And yeah the power creep is intense. At first I tried to balance it but it prouved challenging and in the end I just optimised for the fun ^^ it's nice to break the game sometines, and we still stay to collect all the cards!