Load the Instant Pot with the beef shoulder, salsa, enchilada sauce, broth, onion, garlic, salt, and pepper, then secure the lid. The roast should sit in the seasoned liquid with the aromatics around it.

Set the valve to Sealing and choose Manual, High Pressure, for 40 minutes. Wait for pressure to release naturally before opening; the beef should be tender enough to shred.

Transfer the roast to a large bowl, leaving the cooking liquid in the pot, then pull it apart with two forks or a hand mixer and mix in 1 cup of that liquid. The shredded beef should look evenly sauced without a watery pool beneath it.

Empty the remaining cooking liquid and sliced onions from the pot. Keep the moistened shredded beef in its bowl for assembly.

Submerge the corn husks in a pot of hot water and hold them down with a plate or bowl for 1 hour, or until softened. A ready husk bends easily instead of cracking at the fold.

Heat the shredded cheese and cream cheese together in a large microwave-safe bowl, using 30-second intervals until fully melted. The cheeses should form a soft mixture with no firm cream cheese pieces remaining.

Work the tallow, almond flour, baking powder, psyllium husk, and cumin into the melted cheese with a spatula or your hands, then portion into roughly 2-inch balls. The thoroughly combined dough should be thick and cohesive, with a consistency resembling stiff peanut butter.

Place a softened husk glossy-side down, center a dough ball on it, and press it into a flat round with a spoon back or spatula. Keep the disc evenly thick so it can enclose the filling without bulky patches.

Spoon the beef into a narrow line along the middle of the dough. Leave dough exposed on both sides to form the enclosing seam.

Lift one husk edge to bring the dough over the beef, peel the husk away, repeat from the opposite edge, then roll the husk around the enclosed filling and fold its bottom upward. Each finished package should have masa surrounding the meat, a folded bottom, and an open top; repeat with the remaining portions.

Pour 1 cup water into the Instant Pot, add the steam rack lined with spare husks, stand the tamales folded-end down, and cook on Manual for 20 minutes before allowing a 10-minute natural release and releasing the remaining pressure. Keep the open ends pointing upward so the filling stays contained above the water.

Lift the cooked tamales out of the pot and unwrap them for eating. The corn husks are wrappers, not part of the edible tamales.