Cut the bacon into small pieces (I use kitchen shears) and add it to your Instant Pot. Press the sauté button and cook, stirring occasionally, until the bacon is just about crispy and the fat has been rendered out.
Meanwhile, prep the onion, carrots, and celery. When the bacon is ready, add them to the Instant Pot and continue sautéing for 4-5 minutes.
Stir in the garlic and cook for 30 seconds.
Add in the lentils, tomato sauce, chicken broth, smoked paprika, and cumin. Give it a good stir and ensure nothing is sticking on the bottom of the Instant Pot.
Close the lid, set the valve on "sealing", press the "manual" button and set the timer for 15 minutes. It'll take about 10-15 minutes for the Instant Pot to get up to pressure.
Once the countdown has finished, let the pressure release naturally for 15 minutes, and then do a quick release for the rest of the pressure.
Season the stew with salt & pepper as needed. If you want this to be more of a soup (or you feel it needs more liquid in general), add in more chicken broth and press the "sauté" button to help it warm through.