San Francisco versus San Diego trip

my boyfriend and I are planning on going on vacation September 4 through September 9. At first, I was only considering going to San Francisco. I wanted to go visit Alcatraz, the Golden Gate Bridge, the painted ladies, and go to a Giants game. But I have been seeing a lot of videos about San Diego, It looks so beautiful. I’m not sure if it would be more expensive to visit San Diego. I do think going to the beach one day would be nice, but I don’t know if you can do that in San Francisco. We went to SoCal last year, Laguna Beach, Malibu Beach, and Santa Monica. I want something different than that trip, but I do think a day at the beach would be nice. I also would prefer not to rent a car and would rather Uber everywhere.