In the body of a stand mixer, add the beer (or water), yeast, and granulated sugar, and stir a little just to combine. Let sit for 5-7 minutes, or until bubbly.
Add the flour, and salt to the bowl, and with the dough hook attachment, stir until the mixture starts to come together. Place the speed on medium and knead the pretzel dough for about 5 minutes, or until a dough ball forms. If the dough sticks to the sides of the bowl, add a very small amount of flour at a time until lit doesn't stick (1 tablespoon at a time). If it sticks to the very bottom, that's okay.
On a lightly floured, clean work surface, knead the dough a few times to bring it together and form a ball. Cut the dough into four equal pieces. Roll the dough into a long rope shaper about 12 inches long. Form into pretzel shapes, continue with the remaining dough, and set aside.
Make the Baking Soda Water: Whisk together the warm water and baking soda in a large bowl. Place dough into the mixture until fully submerged. Be careful so the pretzels keep its shape. Spray the basket of the air fryer well with cooking spray, or line the basket with parchment paper. or aluminum foil.
Preheat the air fryer to 350 degrees F, and set the cooking time for 6-8 minutes, in a single layer, flipping halfway through. Pretzels should be a dark golden brown when done. Be careful not to overcook, and take a little peek into the air fryer during the cooking process.
As soon as they are done cooking, brush them with butter and sprinkle on your desired amount of salt. Repeat with the remaining uncooked dough. If you want to make cinnamon pretzel bites, in s small bowl, add 1/2 cup of granulated sugar, and 2 teaspoons of ground cinnamon and mix well. Then dip your pretzels into the butter, and then sprinkle the cinnamon sugar on top.