I will try this out and see how it goes. Thanky for advice.
But i have to say something else as well. The way he looks at me sometimes.... i have this feeling he's completly scaning me and taking mental notes 😂
He is doing exactly that!!
Many years ago when I got Gunnr, her owner too had passed away. Gunnr was with a trainer when we went up and got her. She was 11 months old at the time.
That dog did not look me in the eye for months. Not once. She would look to see where I was, glancingly, but she never looked directly at me.
Start off with him in the house, with little to no distractions, especially another dog. Put him on his leash in the house and walk him at the heel. Keep working with him free of distractions. Lots of praise for anything good, and just a non emotional correction for the not good, but always finish on the positive.
Never, ever, let any dog pull you. The moment he pulls, you mentally turn yourself into a fence post, or tree. You do not break your feet. Put yourself in a solid, weighted ,position and you just stand there, immobile. He wants to keep pulling against that collar and choke himself, let him. You do not move. He will correct himself, or stop breathing. It's up to him. This is kind of a mental game for you, but you can do it. A very small person can mentally convince1200 lbs of horse to not pull, the same can be done with a 60 lb dog.
The moment he back off a little back, you bring him back to you. You don't go to him. There should always be slack in a leash, no matter the length. Pulling is a very bad habit, that can cause injury to the handler. He's got a lot of power, and he could easily pull you off your feet, if you were unbalanced, and hurt you.
If the trainer/coach has him under control. I would work with the trainer coach for awhile, with the dog. Basically, you would be the one being "trained", so don't let your ego get involved. It's the dog that has priority.
The half hitch that Texas Red mentioned is the same technique I use, but you'll need a different leash.The leash comes off their collar, goes toward the back end, loops under the abdomen and then comes back up to your hand. It needs to be wide 25-30mm so it doesn't pinch and bind.
Stop using the collar you currently have and get a 25mm wide, leather D ring safety collar for quick leash work, and short trips.
You need a harness. Put him in the harness and attach the leash to the harness. 60% of a dogs power comes from the front end. Pick up the front end, and they can't pull. It's also easier to pull them back to you and get them in frame for the heel.
In America we have a device called a Halti Leash. It's an adaption of a bitless, or war, bridle for horses. I personally do not like them but they do work very well. I don't like them because they put the dog in an un-natrual heel position in my mind. That's just my personal opinion though.
Last resort is a choke, or pinch collar. If you are not very experienced with these collars, do not use them without guidance. You can do severe damage to a dog used incorrectly. It would be months of non compliance with other methods and collars, before you would progress to this type of collar. Some people use them straight off the bat, but some people will also shank a horse just"because".
Give things time, but do get in touch with the trainer and have them work with you and the dog.