In a small bowl, add the paprika, the cayenne pepper, the onion powder, 2 teaspoons of the garlic powder, 1 teaspoon of the black pepper, 1 teaspoon of the salt, the dried thyme, and the dried oregano and whisk to combine.
In a shallow bowl, add the steak pieces and 2 tablespoons of the avocado oil and toss to coat thoroughly.
Add the seasoning mixture to the coated steak pieces and toss to coat well on all sides.
Allow the steak pieces to sit at room temperature.
In a large bowl, add the potatoes and enough of the water to cover them by about 1 inch and let them sit until the excess starch is removed, about 10 minutes. Drain.
In a large pot, add the potatoes and enough of the water to cover them by about 1 inch, then add the extra salt.
Place the large pot over high heat and bring the water to a boil. Cook until the potatoes are fork-tender, about 9-12 minutes.
In a large skillet over medium-high heat, add the remaining avocado oil.
Add the seasoned steak pieces to the hot oil, working in batches as needed to avoid overcrowding, and cook, without stirring, until the bottoms are golden, about 2 minutes.
Flip the steak pieces and cook for 1 minute.
Reduce the heat to low and cook until the steak pieces reach an internal temperature of 135 degrees F for medium-rare doneness, about 1 minute.
Transfer the steak pieces to a clean shallow bowl.
In the same skillet over medium-high heat, melt 3 tablespoons of the butter.
Add 1 clove of the minced garlic to the melted butter and cook, stirring frequently, until the garlic is fragrant, about 1 minute.
Add the steak pieces to the garlic-butter and toss to coat for 1 minute.
Transfer the steak mixture back to the shallow bowl and tent it with foil to keep the steak pieces warm.
Drain the potatoes and return them to the pot.
Add 6 tablespoons of the melted butter and the warmed half-and-half to the potatoes and mash until the potatoes are smooth.
Add the Monterey Jack cheese, the remaining garlic powder, the remaining 3/4 teaspoon of the salt, and the extra black pepper to the potato mixture and mash until combined and the cheese has melted. Keep the mashed potatoes warm.
In the same skillet used to cook the steak pieces, over medium-high heat, melt the remaining 2 tablespoons of the butter.
Add the remaining 9 cloves of the minced garlic to the melted butter and cook, while stirring, until fragrant, about 1 minute.
Add the heavy cream to the skillet and stir to combine.
Bring the sauce mixture to a simmer and cook, while stirring, until it has reduced, about 3-5 minutes.
Add the red pepper flakes, the green onions, and the parmesan cheese to the sauce mixture and stir until the flavors meld together, about 2-3 minutes.
Scoop even portions of the mashed potatoes onto serving plates and evenly top with the steak bites and the parmesan cream sauce.
Serve the steak bites garnished with the parsley.