Never try to grab the collar - it puts your hand/arm by their face. Instead, the prevailing advice is to grab both back legs and wheelbarrow the dog so that the back legs are both off the ground. It forces them to stop jumping, keeps you away from their head, and makes it so they can’t turn and start on you. Also, it’s a move that can be done on most dog sizes regardless of strength of the person. I’ve done this three times with success in high stress situations like you’ve described (and I’m a fairly small woman).

(I offer this as advice to anyone reading this, not as a criticism. You did a tremendous amount by stopping to try to help to begin with, much less how you kept doing whatever you could think of. You did an amazing thing by helping like that.)

Also, for owners, lifting a dog up is a pretty much guaranteed way to rile an attacking dog up even more (and put yourself at increased risk) because of how dogs react to the confusion of a dog being held aloft above them. So if it’s a situation where someone needs to lift their dog up, they absolutely have to also try to remove themselves in any way possible from the situation. I’ve seen so many times owners of small dogs at dog parks lift their dog up when they felt another dog was playing too hard, and all of a sudden a bunch of dogs would react and start jumping, but the owner would just stand there or shriek around in circles and not even try to leave - like at that point every second they stay, the situation is made worse. Harder to leave the situation when it’s not a fenced-in dog park so the other dog can more easily follow, so that may not have been possible in this situation, but just want to flag this because I think a lot of owners aren’t aware of the effect that lifting a dog up will often have on other dogs.