Prismata is the best 1v1 turn-based competitive game. It even looks and feels somewhat like Starcraft.

It isn't very pooular, which I blame on bad tutorial and monetization decisions. It used to have just a series of missions for learning the game but in an attempt to make it palatable for a wider audience, the developers replaced it with a story and way too easy tutorial missions. The monetization is random loot boxes which doesn't fit well, as the game itself has no rng.

Unlike Starcraft, Prismata can be mastered simply by playing. (I went from bronze to gold in SC2 by not playing the game for years. It helped me focus on actually important things instead of getting my build order timings just right.)