Preheat your oven to 400°F (200°C).
Spread frozen hash browns onto the prepared baking sheet in a single layer, drizzle olive oil over them, and season with salt and black pepper. Bake for 20 minutes, flipping halfway through.
In a skillet over medium heat, cook turkey bacon for 6 to 8 minutes until crispy. Transfer to a paper towel-lined plate.
In the same skillet, cook eggs to preference—sunny-side up or scrambled, then keep warm.
Whisk together egg yolks, Dijon mustard, and grape juice vinegar in a heatproof bowl. Place over simmering water and gradually add melted butter while whisking until thickened. Stir in lemon juice, cayenne pepper, and garlic powder.
Assemble the breakfast poutine with a layer of hash browns, topped with eggs, shredded cheeses, gravy, and hollandaise sauce, finishing with crumbled turkey bacon. Serve immediately.