Cook bacon in a large skillet and over medium heat, turning occasionally, until crispy, 10 to 12 minutes. Transfer to a paper towel-lined plate with a slotted spoon, leaving bacon grease in the skillet. Crumble bacon when cool to the touch.
Add celery and garlic to the skillet and cook in the bacon grease until celery is tender, 3 to 4 minutes. Add cauliflower, water, and onion powder; cover skillet to steam cauliflower. Cook, stirring every so often, until cauliflower is tender, about 5 minutes.
Add milk, 1 3/4 cups chicken broth, and hot sauce. Bring to a boil.
Meanwhile, whisk flour into the remaining chicken broth in a small bowl and drizzle into the boiling chowder. Add Cheddar cheese and 1/2 of the crumbled bacon. Stir until smooth and cheese has melted.
Season with salt, pepper, and hot sauce. Ladle into bowls and top with remaining bacon.