Q.flea beetle control
Is there a jalapeño vinegar mix that is effective against flea beetles and, if so, what is the recipe and how safe is it? Flea beetles (black variety) are eating the leaves and perhaps roots of my Brassica–kale and collards mainly. They are also in the leaves of my radishes.

Flea Beetles are a nuisance but generally will not kill your plants.
Here is a link about how to deter them and a link to homemade pest control.
https://www.gardeningknowhow.com/plant-problems/pests/insects/what-are-flea-beetles.htm