Make the peach filling: In a small pot, combine the cubed peaches, 2 tablespoons granulated sugar, and lemon juice. Cook over medium heat for 12 to 15 minutes, stirring and lightly mashing, until juicy and beginning to thicken.
In a small bowl, stir together the cornstarch and 1 tablespoon water until smooth. Stir the slurry into the peaches and cook for 2 more minutes, until thick and jammy. Transfer to a bowl and let cool completely.
Make the tangzhong: In a small pot, whisk together 0.75 cups water and 0.25 cups of the bread flour until smooth. Cook over medium heat, whisking constantly, for 4 to 5 minutes, until thick and paste-like. Scrape into a bowl and let cool slightly.
Make the dough: In the bowl of a stand mixer, combine the remaining 3.67 cups bread flour, 0.33 cups granulated sugar, instant yeast, and sea salt. Whisk to blend.
Add the cooled tangzhong, whole milk, 0.33 cups heavy cream, egg, and vanilla to the dry ingredients. Fit the mixer with the dough hook and mix on low speed for about 2 minutes, until a rough dough forms.
With the mixer running on low, add 6 tablespoons softened butter, 1 tablespoon at a time, letting each addition fully incorporate before adding the next. Continue kneading on medium-low for 8 to 10 minutes, until the dough is smooth, elastic, and slightly tacky.
Turn the dough out, pull the edges underneath to form a smooth ball, and place it seam-side down back in the mixing bowl. Cover the bowl tightly with plastic wrap and let rest at room temperature for 30 minutes.
Prepare the pan and filling: Line a metal 9×13-inch baking dish with parchment paper. In a medium bowl, mix 0.5 cups room-temperature butter, brown sugar, and 1 teaspoon ground cinnamon until smooth and spreadable.
Shape the rolls: On a lightly floured surface, roll the rested dough into a 15×21-inch rectangle with a long side facing you. Spread the cinnamon-butter mixture evenly over the dough, leaving a 1/2-inch border along the top long edge.
Gently spread the cooled peach filling over the cinnamon layer. Arrange the very thinly sliced peaches evenly over the top.
Using a pizza cutter or sharp knife, cut the dough crosswise into 12 strips, each about 1 3/4 inches wide. Working one strip at a time, roll it up snugly away from you into a spiral.
Carefully transfer each roll to the prepared baking dish, arranging them evenly with a little space between each.
Cover the pan with plastic wrap and let the rolls rise at room temperature for 1 to 2 hours, until noticeably puffy and nearly doubled in size. Near the end of the rise time, preheat the oven to 325°F.
Make the crumb topping: In a small bowl, combine the all-purpose flour, 1 tablespoon granulated sugar, remaining 1 teaspoon ground cinnamon, and melted butter. Stir with a fork until large, moist crumbs form.
Sprinkle the crumb topping evenly over the risen rolls. Bake for 30 to 40 minutes, until the rolls are golden brown and the centers are baked through.
Place the pan on a wire rack and let the rolls cool for at least 15 minutes while you make the glaze.
Make the glaze: In a small bowl, mix the cream cheese and 4 tablespoons room-temperature butter until smooth. Add the powdered sugar and stir until combined, then whisk in 2.5 tablespoons heavy cream until the glaze is smooth and pourable.
Spoon or drizzle the cream cheese glaze over the warm rolls. Serve warm.