If you can lead him in just fine, then the problem is the incompetence of the others.
Unfortunately, there is nothing you can do to transfer handler competence to other handlers.
Training the horse some more is not going to train the idiot humans.
I know you said you don’t want to move, but it’s probably the only option if you don’t want to beat your head endlessly against the wall with other people’s incompetence. At least if you up and leave immediately, you can just say, “Looks like leading Ranger in and out of the field is pretty tough for you guys but I need to make sure he’s kept safe, guess you’re forcing my hand here…”
There is a chance if you say you need to leave and lay it on them they will start arguing with you to stay and that they are excellent handlers. Some passive aggressive people like to use vague threats of “guess you might have to leave” to try to get you to validate their concerns, subjugate yourself to them, and basically beg them to “let” you stay. The whole tone of the conversation forevermore revolves around your horse being the problem and it being on you to figure this out and appease them, even though it’s really on them to be remotely competent at their chosen profession.
If you refuse to cater to this and say, “You’re right. I guess both Ranger and I would feel more comfortable somewhere with more experience in handling horses like Ranger, and I really can’t have him getting led around in a group of 4 risking reinjury,” there is A CHANCE they will realize you’re not fng around and that they will start arguing with you that they are excellent handlers, volunteering to bring him in by himself, and you should stay. It’s really a last ditch hail mary, because by the time the incompetence nattering starts, it’s usually inevitably all over. It either gets nipped in the bud immediately or the “your horse is the problem” dynamic takes over your entire life and you eventually have to leave anyway.
Believe me, I get it. I have gotten more than my fair share of phone calls blaming the horse when human incompetence was the real problem. People who can’t lead horses competently shouldn’t work at or own boarding barns, but they do, and here we are.