Blend Greek yogurt, cottage cheese, milk, maple syrup, vanilla, cinnamon and salt for 30 to 45 seconds until completely smooth.
Stir rolled oats and chia seeds together in a large bowl so the chia is evenly distributed.
Fold the dairy base into the oats until no dry pockets remain; rest 5 minutes, then stir again to break up early chia clumps.
Divide the mixture among four clean 16- to 20-ounce containers, leaving room for fruit and stirring.
Cover immediately and refrigerate at 40°F or below for at least 4 hours, preferably 8 to 12 hours.
Stir each jar, add milk 1 tablespoon at a time if too thick, and top with berries and optional almonds just before serving.