The best thing we ever did was put our guy into a 2 week intensive live-in training course.
These guys aren’t in your area, but if you can find something similar around you, I would absolutely recommend it.
https://www.thecanineclassroom.com.auThese guys partner with a boarding kennel and the trainers go to the kennel to run intensive course with the dogs while staying there.
Our boy is an American Bulldog X Great Dane X some other things, most likely Boxer. He’s a great natured dog, but with his size he was hard to walk on the lead and his recall was hit and miss (at the beach there was no stopping him bolting off to play with everything he saw).
After the 2 week stay he has turned into an almost perfect pooch. He’s got all of the sit, drop, stay commands nailed pretty good. We do a short little training session on the driveway before we go on our walks and there’s no more pulling on the lead.
The hardest one for him is staying close to us when off lead and not getting distracted, while he’s not perfect at this, he is 100 times better then before we did the training.
I would highly recommend these training guys to anyone around this part of the world.
If you can find something like this in your area I recon it’s worth the money, it’s not cheap....