4 month old puppy – potty training

Hi, I have a 4 month old mutt potentially a German shepherd, husky and standard poodle mix. He’s very sweet and smart, we had him for a month and he’s doing really good. He goes to the door to go outside for peeing and pooping. We put him in his crate at night and when we go to work these are both around 7 hours. He never pees or poops in his crate so we know he can hold it however when he’s not in his crate and we’re home he wants to go outside to pee very frequently sometimes every 10-15 minutes. What should we do? We know he can hold longer if he could and it’s great he’s going to the door and not peeing inside (he does if we don’t take him out when he goes to the door every 10 minutes 🤦🏻‍♀️) but how can we teach him how to hold it longer when he’s not in his crate too?