Yea, this can be a frustrating hobby. There are SO many variables...
FWLIW, most of my OW plants down here in S. Az - with winter/spring temps about 5 degrees warmer than Vegas - are flowering well.
That said, there is plenty of variability between plants. My Fatalii already has at least 100 pods going well, while the Bih-J is just now setting tiny fruit. Why that would be, I can't begin to guess.
(The Annums are already ripe!)
I've been using a weak dose of plain old 24-8-16 MG with each watering. About 1/2 teaspoon in 2 gallons.
Plus an occasional dash of epsom salt and occasional dash of home-brew calcium acetate.
All I know to suggest is to make sure they're not getting water stressed. That and perhaps try experimenting with your fert dose. They may want more, they may want less, they may want something else entirely.
What sort of sun do they get? Earlier in the year, as new foliage was coming in, my plants seemed a bit stressed by too much direct sun. Placing them where they got mid-day shade seemed to help, and just might have improved blossom set.
Good luck!