What is the diference between a quinoa burger, a quorn burger, and a soya burger?
The differences are as follows:

Quinoa is a pseudocerial coming from goosefoot wikipedia. It is one of the trendy "superfoods" because it has a very high nutritional value ánd is gluten free. I have always used it as a grain substitute and do not know if it's any good as the main ingredient for a burger.

Quorn is a meat substitute made of mycoprotein from fungus. wikipedia. In my personal experience quorn is a very acceptable substitute for ground beef, so a burger made of this material is likely to taste pretty decent.

Soy is a plant material traditionally used for instance in tofu. It has long been used as a meat substitute due to the high protein content. In my humble opinion it has been surpassed by other meat alternatives, mainly because soy based meat alternatives lack in texture.

All very different products then, where most likely the only common factor is the spicing.