Last year I raised three batches of angels. I kept the eggs with the parents, and didn't add anything to prevent fungus, I let the parents look after that. If there were any white eggs the parents removed them. I found it easiest to feed the fry freshly hatched brine shrimp, I had no luck with protozoan cultures. I also raised the fry with the parents without issues.
It looks like you moved the cone to be in the water flow. I would have to say that the parents in my case only laid the eggs in lower water flow areas where they would fan the eggs. Obviously I had some luck in that my parent fish were not inclined to eat the eggs or the young.
When the parents look after them once they hatch they tend to move all the sticky head wigglers to a new location. The parents would start cleaning a new area then one minute all the fry are at the new area.
This is my log of my second attempt at raising angels, my first was unsuccessful.
https://www.fishforums.net/threads/angelfish-breeding-log-2nd-attempt.472784/. I used information from various forum members to help with raising them.
To answer your question directly I think the eggs are too close to the airstone.