Ortho prods are good, but get the liquid you can put into a pressure sprayer.
You need to spray all the cracks and crevices. Widows are hiders.
I live in an area of Tucson that is known for widow infestations.
You need to heavily spray where you saw them, taking care to hit corners and undersides.
Then you need to cut back vegetation.
The reason you are getting nests/hives is because there is a food source.
Ants, flies and especially grass moths are a favorite of widows.
Keeping your vegetation cut back from the affected area, and a regular spraying will help.

As a Man terrified of spiders, I wish you well!