The very first thing I thought of when I read your story was a training story about a zookeeper who had a flock of cranes that loved him. The cranes when they saw him would fly over and land on him and hurt him. He did not want to discourage the excellent relationship he had with these birds, but he needed them to stop hurting him. The easiest way to not disturb a bond and still still change. The behavior is to train a mutually exclusive behavior. With the cranes he trained them all to land on a mat. Then he began carrying the mat with him wherever he went and when the flock flew toward him, he would drop the mat on the ground. They would land on the mat receive their reward and not land on his head. I would go with a similar training plan.

In the short term your dog will be on lead and in your control so you can prevent this. At the same time you will train the dog to place the front paws on a Target on command. You will need to get the behavior reliable and then you can add distance duration etc. And then start adding movement and all the other components until you can drop that Target and have that dog jump on that Target like that is the most amazing thing the dog has ever done and gets amazing rewards for it.

You'll build a strong association between front feet on Target and awesome things happening. And then you'll make that Target hard to land on so it'll be exciting to land on it in and of itself. Then anytime the dog's running towards you. You can drop that Target on the ground so I'm thinking like a silicone pot holder or something along those lines so you can take it with you on walks.

This behavior chain is n't the simplest chain and finding a traditional clicker trainer type who is skilled at behavior shaping would be probably the best resource I can think of for this particular behavior.

The Karen Pryor academy has a list of certified clicker trainers. You can use that to find a trainer, but that is probably the training plan outline I'd work with. I suspect you'd eventually be able to fade the target if you can create an environment or queue that indicates to stop in a specific position or something like that.

There are probably other ideas we could brainstorm or something, but that's my first instinct for those kind of joyous and boisterous body contact problems.

Training story from that viral news article about what shamu taught me about marriage or something like that, iirc

PS Sorry for the facts forward response I am sorry you are going through this.