Probably not enough water, too much fertilizer, and leaf burn from the spray all combined with he heat. In your temperatures, tomatoes will not set fruit at all. They need double the amount of water that you are providing just to survive and wait on cooler temperatures. Less fertilizer when it's hot, or you will burn the roots. And nothing sprayed on the leaves to burn them in the heat. If the temps are over 80, don't spray anything at all, especially anything oil based. Nothing with any insecticides or fungicides on edibles, ever.

Thanks Sophie, I'll increase the water, won't add any more fertilizer and see how things go.

I didn't add the spray till after the heat and only applied it in the evening when temps were lower. The spray says its for Tomato's and Veggies specifically, so I'm not sure if you have a different opinion.

From doing a bit more research, I'm starting to believe I have Bacterial wilt. Showing a lot of the symptoms. Thanks for your input.

My Black Cherry did better with significant shade than it did with full sun (but the soil may have been the issue).

Also, you might wish to dig down a little bit and peak at the root system of the weaker plant. Try not to disturb it much. You may have hidden soil pests like soil aphids, ants, or even root knot nematodes. I'm in zone 10b, growing black cherries too. They do like a bit of shade from the hottest part of the day (afternoon). And I water twice a day (I've got them in pots, OFF the ground because of nematodes). When it gets really hot, I use the 'shower' setting on my hose to shower the with cool water during the afternoon. During our summers, I actually still have tomatoes because I set up shade cloth canopies, shower them with cool water, and even dump ice cubes around the outer rim of the pot for cold melting water supply.

You mention drip irrigation for only 20 minutes? That ground looks hard and dry dry in the pictures. I'd change that to at least an hour. Tomatoes need a lot of water. Do you have compost (use it as mulch) on them to conserve water? Maybe you need some more compost/humas dug into the planting area. The color of the ground looks(?) as if there isn't enough organic material in the dirt. But that could just be the picture?

Wilts are a problem for sure. That does look like leaf curl due to lack of water, or leaf burn to me... yet your picture shows a lot of shade on the plants. Sometimes, when it's cooler and wet, it's more of a case of wilts.