Pick over the peas to remove any debris, rinse well, and soak in plenty of cold water overnight (8β12 hours). Drain before cooking.
Put the bacon in a large heavy pot or Dutch oven over medium heat and cook until the fat renders and the edges turn golden, 6β8 minutes.
Add the yellow onion and celery and cook, stirring occasionally, until softened and translucent, 6β8 minutes.
Stir in the garlic and cook until fragrant, about 30 seconds.
Add the smoked ham hock, the dried black-eyed peas, the chicken broth, low-sodium, and the water. Stir in the bay leaves, dried thyme, black pepper, and cayenne pepper. Bring to a simmer, then reduce the heat to low so the liquid just barely bubbles.
Simmer partially covered until the peas are creamy-tender and the meat on the hock yields easily, 60β90 minutes, stirring occasionally to prevent sticking.
Lift out the hock; discard the skin and bone, chop the meat, and return it to the pot. Discard the leaves. Stir in the kosher salt and the apple cider vinegar and simmer 5 minutes more to meld flavors.
Taste and adjust seasoning with more salt or pepper if needed. Serve hot with hot pepper vinegar (for serving), alongside cornbread or rice.