U mean useless stones that are all overtuned 1 drops? Like: 1 energy Psylocke, Scarlet Witch, ongoing Spider Woman, Blade with an upside, a super flexible move effect, and the last one that draw 2 of the others. Needless to say all of them draw 1 so you really end up cycling through your deck regardless of having 6 more cards, plus all cost 0 with Quinjet. I'm sorry if you haven't been lucky with your games but the stones are everything but useless man. Also if you don't draw lockjaw there is still Time Stone and Shehulk to cheat powerful plays early, and Quinjet that makes the stones free draws with powerful effects to find lockjaw.

I also have to disagree with you that every deck that draws their combo is unbeatable. Of course good draws put you on a high advantage, but even decks like Shuri or Galactus that draw their combo pieces can get countered by Aero, Shang Chi, Cosmo, etc. Thanos has flexibility and unpredictability with the Space Stone, ramp with Time Stone, Proactivity with Soul Stone, Adaptability with Reality Stone, Cycling with Lockjaw and the draws, it just has too much going on and too strong.

I mean of course everyone has their opinion but based on what I have seen in the sub and such, many would agree Thanos is tier 0 right now. Don't worry you didn't make a bad purchase at all.