Season meat (chicken and beef) on both sides with salt. Let sit at room temperature for at least 15 minutes so the salt can do its job.
Heat a Dutch oven or large heavy-bottomed pot over medium-high heat. Add oil to the pot.
Then, add the meat and chicken (doing so in batches if needed to avoid overcrowding) or brown the beef and chicken separately. Let it sear for about 2 minutes before turning the chicken over.
Cook for about 6 minutes or until browned. Then add the sausage and cook for a couple more minutes.
Add sofrito, garlic, cumin, paprika, oregano, and sazon. Sauté until fragrant, about a minute. Then add the onion and cook for about 5 minutes.
Pour in the broth, return the meat to the pot, and bring it to a boil. Lower the heat and simmer for 15-20 minutes, depending on your cut of beef. Cook less time if only using chicken.
Next, add the root vegetables, starting with those that need more cooking time—in this case, the green plantains. Cook for about 10 minutes before adding the yuca, squash, potatoes, and corn.
Continue simmering the stew for 10 minutes until the meat and veggies begin to soften.
Adjust salt, pepper, and other seasonings to taste.
Continue cooking until root vegetables are tender, 15-20 minutes. The stew should be thick and hearty; if not, mash up a few root vegetables to thicken it.
Serve in large bowls and top with chopped cilantro.