Rinse the beans and pick through them to remove any stones. The source says soaking is not necessary.
Set the Instant Pot to Sauté Normal and add the avocado oil. When the pot is hot, add the sausage and brown for 6–8 minutes. Remove the sausage and set it aside, leaving the browned bits in the pot.
Add the onion, bell pepper, and celery. Cook for 3 minutes, stirring as the vegetables release moisture and loosen the browned bits. Add the garlic and cook for 1 minute more.
Press Cancel. Add the broth or water, Cajun seasoning, smoked paprika, thyme, bay leaves, and beans. Stir, secure the lid, and pressure-cook on Manual/More for 45 minutes.
When the timer ends, press Cancel and quick-release the pressure. Once the pin drops, remove the lid.
Remove 1 cup of beans, mash them, and return them to the pot with the reserved sausage. If the sauce is too loose, use Sauté More to reduce it to the desired thickness.
Serve over cooked rice and top with chopped scallions and fresh parsley.