I just tried with a different char and felt a little better, more fluid experience. But I still think we need more reasons to master the Tetris part. I see it more a patience and build-up game than a puzzle or action. I make a pile with just 1 column of empty space. In this way I can make the biggest combo, with 4 lines at once. Sometimes I do indeed need to destroy my pile and break the combo, but I see it as an challenge to restore my original plan.
You should add something that have this feel of building up an "immense power". Cleaning just one or two lines in Tetris I think is boring since you rarely will face the challenge of a 4-line combo that goes wrong when your screen is already filled with blocks.
Did you check the game Peglin? It's demo is free on Steam right now. Is a game in which the damage dealt in combat is the same as the points you make in a pachinko-like minigame. Maybe you can have some ideas from there.
Good luck!!
P.S. I think I never before wrote so much about what I fell playing Tetris! hahahhahahaha