A two antenna solution with a UVSJ is best, but here’s an idea that works only in your section of San Diego.
If you can find a discontinued Winegard HD-1080 it works on both UHF and VHF with the pattern of the two bands aimed in opposite directions, which is exactly what you need. If the pattern on the spec sheet is accurate, you can gain a bit by installing the antenna upside down.
https://manuals.solidsignal.com/hd-1080-spec.pdf
Here’s one supplier that I found. It’s on sale for $25.
https://www.swidenonline.com/product...na-2bay-hd1080