I always considered hitting a horse abuse
That there is your problem. There is nothing wrong with one good hard whack.
With the tying, honestly, tie him solid in a rope halter with no clip on the lead rope (any metal creates a weak spot). He is old enough to learn to give in to pressure sooner or later. You just walk away and leave him for a while. Have someone supervise him in case he's really going to hurt himself, but if you're likely to cave in to his protests, don't be within eyesight. Both my horses tie solid, I don't use twine because I have had a horse learn to pull back when it broke and he got loose. I can walk away and leave them for literally hours at a time and never a problem.
If you ask him to go forward, he GOES FORWARD. I don't care how much force it takes you to make him move, the important thing is that you make him move. I know some people who wait them out and then make them stand a little longer, but honestly, if a tree is coming down on top of you you don't have TIME for that. IMO you should ride, all the time, like you expect your horse to respond and do as it's asked RIGHT NOW, just in case you really do need to get somewhere in a hurry.
Loading can be a fear thing, or it can be a stubbornness thing. My gelding was terrified, at first, after falling twice in a transport truck on his way to me. My mother was the first one of us to try to load him and he flat out refused, so she gave in because she didn't have a lot of time. Ever after that, he was a nightmare until we MADE him go on. He now loads easy every time and sometimes self-loads. He self unloads every time easy and calm.
Horses are big, dangerous animals, so it's imperative that they respect you. A large part of that respect is you ask, they do. Right away without protest. To teach them to respond, you start really small, with a very gentle ask... like a please, pretty please will you? And then you tell them (for example with the hill) "walk on". And then demand. "WALK ON". And then a promise, and this last phase has to be REALLY good, because it's your last resort. "YOU WILL WALK ON RIGHT NOW OR YOU'LL BE SORRY".
it's sort of like, with the walk, a little touch with your heels. Then a squeeze. Then a little kick. And last but not least a big cadenza, HUGE kick, whip, spur, whatever you have to do to MAKE that horse move.
Start this in the round pen at first, a controlled space. Make sure that when your horse does move, you don't catch him in the mouth, and just let him go for a few strides. Then bring him back gently, and start again from the very softest of asks. They learn very quickly. It will seem to the outside observer that the horse is having a big panic but they are actually perfectly calm once they understand what's going on.
Be aware that if YOU are the one to do this, he will escalate his behaviour and try to dominate you. Whatever you do, don't give in. Just keep at it until HE gives in. Even one step is progress. Even half a step is progress. If he moves in the direction you ask him to move, even the slightest little bit to begin with, then YOU have won.
The important thing to make sure you always do, is get what you're asking out of the horse... even if you have to take a step back and ask for it a little simpler, as long as you finish on that good note you have won and he will learn that you are the boss.
Edit to add; the problem you have is because you seem not to have gone past the "please, pretty please" and so he has gotten away with ignoring you. Horses always take the easy way out, and if you make it easier for him to do as he is told, then he will do as he is told. You haven't been doing this, so he hasn't been behaving himself.