Slice the top round roast into thin strips and place in the Instant Pot with beef broth, garlic powder, salt, and pepper. Cook on High pressure for 10 minutes.

Let the Instant Pot naturally release pressure for 10 minutes, then release any remaining steam and set aside the cooked beef.

In a saucepan, melt unsalted butter, then whisk in the flour until golden brown. Gradually add milk until thickened, about 3-5 minutes.

Lower the heat and stir in hot sauce and sharp cheddar cheese until melted and smooth.

Butter both sides of the hamburger buns and toast in a skillet over medium-high heat for 2-3 minutes until golden brown.

Assemble sandwiches by layering toasted bun, beef, and drizzling cheese sauce on top. Cap with the top bun.