8/31/23 update:
Doubled pb. Baked at 325 for 50 mins. Thinner & made 33 cookies. Still hard but not quite as bad. 3 oz milk was about as much as it could handle. Very sticky at first. Needed 30 mins to rest before rolling out. Still hard. Go harder on the pb next time? Or try oat flour instead of whole wheat?

Op:
https://southern-bytes.com/blueberry-dog-treats/

made a half batch, rounded up to 2 tbsp (32g) peanut butter, used dry blueberries, used 1/4 c + 1 tbsp lactose-free milk instead of water, these were meant for me to eat because I'm a little freak so I brushed them with milk and sprinkled with vanilla sugar.

tasty :d idk where they're getting roll to 1/2 inch from I rolled to 1/4 inch thick and the cook time was spot on. any longer and they would have burned.
they're a bit thick/hard to bite into (for human, not bad for dog)

for human consumption... double peanut butter? maybe roll thinner and bake at lower temp?