Joi's Cooking Pressure Cooker Osso Buco

FOR THE OSSO BUCO:
All-purpose flour, for dredging
4 sprigs fresh thyme
2 sprigs fresh rosemary
1 bay leaf
2 ½ to 3 pounds (4 pieces) osso buco (bone-in veal shanks), patted dry with a paper towel
2 teaspoons kosher salt
Freshly ground black pepper
3 tablespoons extra-virgin olive oil
2 tablespoons unsalted butter
1 onion, diced into 1/4-inch pieces
2 medium carrots, diced into 1/4-inch pieces
1 celery stalk, diced into 1/4-inch pieces
4 garlic cloves, thinly sliced
½ teaspoon tomato paste
½ cup dry white wine
½ cup chicken or beef stock, preferably homemade
1 14.5-ounce can diced tomatoes, drained
FOR THE GREMOLATA:
¼ cup finely chopped fresh parsley
Finely grated zest of 1/2 lemon
2 garlic cloves, minced
Pinch of kosher salt, plus more as needed