Set the Instant Pot to sauté on the medium setting; chop the garlic and shallot
When the pot is hot add 2 tablespoons butter; add the shallot, garlic, and pinch of salt and pepper; cook stirring until softened, 3 minutes
Stir in the rice and thyme sprigs; cook until rice is toasted, 3 minutes; stir in the wine, scrap the bottom of the pot; cook until evaporated, 30 seconds; turn off the sauté function
Stir the clam juice and 3 cups of hot water into the pot; close the lid; turn the steam valve to the sealing position; set the pot to cook on high pressure for 5 minutes
When it is done, turn the valve to the venting position and release the steam completely; carefully open the lid
Season the shrimp with salt and pepper; add to the pot; stir in the peas; with the pot still turned off, close the lid and let the shrimp cook through, 5 minutes
Add the parmesan and lemon zest to the risotto; stir in the remaining 2 tablespoons butter until melted; add a few drops of water to loosen; throw away the thyme sprigs; top with lemon zest and serve with lemon wedges