Sort and rinse dried black eyed peas, then soak in cold water for at least 4 hours or overnight. Drain and rinse before using. If using canned, simply drain and rinse, then set aside.
Heat olive oil in a large Dutch oven over medium heat. Add onion, carrots, and celery and cook for 7-8 minutes until onion is translucent. Add garlic and cook for 1-2 minutes more until fragrant.
Stir in dried thyme, smoked paprika, oregano, and crushed red pepper flakes and toast with the vegetables for 30-60 seconds until fragrant.
Add chicken broth, water, drained soaked peas, diced tomatoes with their juices, ham hock, and bay leaves. Bring to a rolling boil over medium-high heat.
Reduce heat to low, cover with lid slightly ajar, and simmer for 1 to 1 1/2 hours until peas are tender. Stir every 20-30 minutes and add extra liquid if needed.
Remove ham hock, let cool, then shred the meat and return it to the pot. Discard skin, bone, and large fat pieces.
If using canned peas, add them now and heat through. Stir in collard greens or kale and simmer for 15-20 minutes (collards) or 8-10 minutes (kale) until tender.
Remove bay leaves. Season with salt and pepper to taste. Stir in apple cider vinegar. Optionally, use an immersion blender to blend 2-3 cups of soup for a thicker texture. Let rest 5 minutes before serving.