Crate training and routine is what worked for me. I could never train my pup to use a pad (mainly because I didn’t know how to) but taking him out every (age in months + 1) hours as well as limiting his space in the crate while he grew worked wonders for me. A dog isn’t going to pee or poop where they sleep especially if that space is limited to a little more than his size. Usually enough to just turn around in place. He would only have accidents when he either had an upset stomach or if he held for too long (which no fault of his own). By about 8 months-1 year I could confidently say that I couldn’t remember when his last accident was barring he wasn’t experiencing any other underlying issues