In my heart of hearts, I believe two very important things:
1— Yes, TOS Kirk is better than Spock at chess, not because he's just a chaos agent or lucky or Spock is distracted and letting him win or any of the other ways of minimizing TOS's extreme clarity on this point. Kirk keeps winning, as Spock himself gradually comes to accept, because Kirk is better at chess.
Behind their mannerisms, Kirk is the cooler-headed and more relentlessly calculating of the two, and fuses not only exhaustive background information but very quick, versatile adaptation and application of information + tactics to changing circumstances, even when the change is highly unexpected. Spock doesn't adapt to breaks in routine or expectation as quickly or as smoothly, and ... lbr, he pretends he's not more of a hothead than Jim Kirk in his totality will ever be, but it's a dirty lie.
2— Speaking of which, once Spock learns poker? He's way better at it than James "any time weird powers strip away my iron grip on my weaknesses I get consumed in analysis paralysis" Kirk. Spock loses now and then through a) monumental bad luck that speaks poetically to him or b) brazen pretense so other crew members will keep the eternal Enterprise poker championship going, rather than getting so disheartened they give up altogether.
Anyone who suggests there's something un-Vulcan about Spock's embrace of poker gets the galaxy's most withering non-expression imaginable. Surak teaches the importance of absolute self-discipline very much including one's facial expressions, seeing multiple possibilities but maintaining commitment to one's decisions, and controlling one's emotions. There is nothing un-Vulcan about Spock's immaculate poker face or evolution into Enterprise card shark.











