People get too caught up in "training" and "skill" and treat the Force as if it's something mechanical, a mana pool that allows you to move big rocks. But the Force is spiritual, it's metaphysical. I guess you can say it was "mindset" but that word doesn't quite capture it either, it's more appropriate for a tennis match or a cooking competition.
Kenobi won because he was at his strongest, Maul lost because he was at his weakest. Spiritually.
Kenobi at that point reached a moment of "oneness", a clarity and an unshakable sense of purpose to protect the child who he knew was the hope for a better galaxy. That's a Jedi at his finest. There was no way he could lose in that moment, not against anyone.
Maul at that point was half-mad and waiting to be put out of his misery. For the whole episode he was wandering through the desert mindlessly muttering to himself and having hallucinations. By that point he had spent decades wallowing in hatred, despair, self-pity and grief. He probably wanted to die.
In my opinion, at that point it's useless to compare them in terms of "saber skill" and "TK feats". It's as simple as this: Kenobi won because he was a winner, Maul lost because he was a loser.