Slice the room temperature beef in large sections, 3-4 inch chunks. Season with salt and pepper. Set aside.
Preheat 3-4 tablespoons of avocado oil in a large dutch oven pot to medium heat for 5 minutes. When ready, sear and brown the beef on most sides, 3-4 minutes per side. Remove from the pot and transfer to a large plate.
In that same pot, add the onion, serrano pepper, garlic and poblano pepper. Stir well to combine, adding a little more oil, if needed. Saute for 3-4 minutes.
Add the tomato and tomatillo. Season lightly with salt and pepper. Saute for 5 minutes. Add the oregano, thyme, marjoram and bay leave. Stir to combine. Mix in the maggi sauce(or worcestershire). Stir to combine, then add the meat back in with all the juices. Pour in 4 cups of water or enough water to cover meat 3/4 of the way.
When it comes up to a simmer, cover , reduce heat slightly to below medium and cook for 1 1/2 hours or until beef is pull apart tender. Taste for salt along the way as beef cooks.
Once beef is tender, remove it from the pot. While it's hot, using two forks, shred the beef finely. Set aside. Remove the bay leaves from the pot. Transfer all of the solid from the pot to the blender jar. To the blender also pour in 4 cups of the broth from the pot. Holding the lid down with a towel, start on low, then blend on high until smooth.
If you want to serve this dish as carne deshebrada with the broth, leave any remaining broth that it's the pot. Pour in the sauce from the blender and mix in the shredded beef. Stir well to combine and cook for 20 more minutes.
If you want to use the shredded beef for tamales mix sauce from blender with shredded beef and not any extra broth from the pot. You want a thicker filling that will work better for tamales. Combine beef and sauce and cook down for 20 minutes. Cool completely before filling tamales. Works best to chill overnight. Slice the cheese into 30 equal sticks(2 inches tall). Cover and chill until ready to use.