Have you heard of Poisuilles Law? It applies to a non compressible liquid, but the same principles apply to gases.
The average diameter of a human trachea is 15-25mm. Diameter of snorkels are 15-25mm. So explain the physics of how you can have increased resistance from the snorkel apparatus itself? I guess if it was kinked.
I don’t think it’s the actual resistance of the snorkel causing pulmonary edema as it is other factors.