Possibly, these visions are the product of physical, psychological, *and* spiritual factors. Remember, Kundalini, itself, is a physical, psychological, and spiritual phenomenon. It operates on all these levels at the same time.
But, in a way, it doesn't matter what the cause of the visions are because the approach to helping yourself with them would be the same. First, you make sure you are taking good care of yourself physically, which you are already doing.
Then, you cultivate a balance in your relationship to them -- you embrace them to some extent, and you create healthier substitutes. Both.
You have had a lot of success in the past with facing scary visions and breathing and relaxing into them. It takes some effort, but you have reported feeling triumphant, excited, more confident and secure when you do something along these lines.
What do you think about trying a comic approach? You could put funny antlers or Groucho Marx eyeglasses on them? You don't have to be serious all the time.
Then, the last suggestion is to redirect your attention some of the time to images that feel more healing and corrective. If you are having any plain white light internally, you could try focusing on that, and letting it fill your field. That's very healing.
Let us know what works best for you, as you experiment!