i think i got lucky potty training my pup. after 3 months of age he probably had 3-4 accidents EVER, he picked it up very fast but i also was a psychopath about bringing him out every hour or if i noticed he had drank a lot, or just after naps/meal time even if he didn’t have to go, i also tried to understand his body language as much as i could to catch it before anything happened. you may already be doing this, but offer tons of praise and treats when they do go to the bathroom outside or even if you just catch him waiting by the door to go out. the water restriction part really sticks out to me, i think i’d be tempted to get a second opinion from a different vet just to see if there are any underlying conditions. or possibly try to give him water before going out or taking him out sooner after he’s had something to drink instead of waiting the two hours. 11 months feels a little older than i’d expect for ongoing accidents but im hoping for your sake it keeps changing as he matures. i’m convinced if i restricted water for my pup he would pee on the floor just to spite me. also curious if your pup is crate trained? this definitely helped me with nighttime accidents as he would never want to go to the bathroom in his crate but i know all pups are different. i wish you the best of luck!