First, put your Instant Pot on the "Saute" setting. Add in the olive oil and minced garlic.
Once the garlic browns a little, you can add the Italian sausage.
Brown them up and this should take about 7 minutes total. Make sure to roll from one side to another so both sides brown.
Add in your peppers and onions once the sausage is finished.
Add in all other ingredients including the tomato sauce and crushed up tomatoes. Do not stir this, just add it all on top of the sausage.
Put the lid on the Instant Pot and seal the valve.
Put the Instant Pot on "Manual" and cook on high pressure for 26 minutes.
Once the timer is up, quick release the pressure, stir it all together, and serve.