Soak lentils: Soak the lentils in water for at least 30 minutes while you chop the vegetables and measure the spices.
Fill the Instant Pot: Drain the lentils and add them to the Instant Pot. Add the potatoes, onion, carrots, celery, garlic, bay leaves, tomato paste, oregano, and thyme.
Add broth: Pour in the broth and stir, making sure all ingredients are submerged.
Cook: Lock the lid in place and set the Pressure Release knob to Sealing. Select Pressure Cook on High for 5 minutes and press Start.
Release pressure: After the 5-minute timer finishes and beeps, let the pressure release naturally for at least 10 minutes. Then, carefully switch the Pressure Release knob to Venting to release any remaining pressure.
Serve: When the float valve drops, open the lid, remove the bay leaves, and stir in ½ tablespoon of vinegar and freshly ground black pepper. Taste and adjust with more vinegar, pepper, or salt as needed. Serve hot and enjoy!