I have to tell you that discovering Tweening has been absolutely amazing for me. Nearly all the animation in the game happens with Tweening, and specifically DOTween which is a free asset on the Unity Store. That and standard Unity UI components. I have used sine curves in other games to create water effects and such which I dont think tweening could handle, and its many times more complex than what we did in this game. I will check out your game.
Edit: Also if you didnt try it, go full screen. I think the upgrade icons look ok full screen? But in a window yes I'd agree the detail gets lost.