Preheat the oven to 200°C (400°F). Lightly grease a pizza pan or baking sheet and set aside.
In a mixing bowl, whisk the almond flour to break up any clumps.
Place the 3 cups low-moisture mozzarella and 1/4 cup cream cheese in a microwave-safe bowl and heat in 20-second intervals, stirring between intervals, until mostly melted and smooth.
Stir the melted cheeses, then add the almond flour and mix. Add the eggs and continue mixing until a sticky dough forms.
Place a large sheet of parchment paper on a flat surface, transfer the dough onto it, and cover with a second sheet of parchment. Roll the dough with a rolling pin to about 1/2 inch thickness, then remove the top parchment and shape the edges by hand to form a pizza crust.
Transfer the crust (on the bottom parchment) to the prepared pizza pan and bake for 12 minutes, until the crust is firm.
Remove the crust from the oven, spread 1/4 cup keto pizza sauce over the crust, sprinkle 1/4 cup shredded mozzarella, and top with mushrooms, bell peppers, and 1 teaspoon Italian seasoning.
Lightly brush the crust edges with olive oil if using, then return the pizza to the oven and bake 10–12 minutes more, until the cheese has melted and edges are golden.
Remove from the oven, slice, and serve warm.