Combine granulated sugar and water in a saucepan and heat over medium heat until the sugar is fully dissolved, then turn off the heat and cool completely (aim for room temperature). Visual cue: the mixture should look clear with no sugar grains at the bottom of the pan.

Add the diced fresh ripe peaches, cooled simple syrup, lemon juice, vanilla extract, and salt to a blender. Blend until completely smooth, stopping to scrape down the sides as needed; visual cue: the mixture should be uniform and glossy with no peach chunks.

Pour the blended peach mixture through a fine mesh sieve into a bowl. Let it pass through, stirring gently; visual cue: the strained version looks extra silk-smooth while the leftover pulp stays in the sieve.

Refrigerate the peach mixture until very cold, then churn in an ice cream maker for 20-25 minutes. Visual cue: it should thicken to a soft-serve consistency as it churns.

Transfer the churned sorbet to a freezer-safe container and freeze at least 2 hours until firm enough to scoop. Visual cue: the surface will be solid with minimal wobble when you tap the container.