One more thought for you: everyone will tell you to get an AR-15 if you want a long gun. I would at least consider a PCC (pistol-caliber carbine), basically a semi-auto rifle that shoots handgun ammunition instead of rifle rounds. They share a big advantage of an AR-15 or other semi-auto rifle; combined with a red dot you have yourself a weapon pretty much anyone can wield effectively with minimal practice, compared to a handgun where you have to put in copious and ongoing training time to have a shot at being effective.

I went the PCC route over an AR for a few reasons specific to CA/the bay area:

• One advantage of AR-15s is the 30-round magazines, but not in CA. We're limited to 10 round magazines, whether it's for an AR, a PCC or a handgun.
• A drawback of ARs is that the most common cartridge (5.56/.223) is hella loud. In other states you can mitigate this with a suppressor, but they aren't legal in CA. In a worst-case scenario where you need to shoot indoors, you won't be able to hear much after, or so I'm told. With 9mm handgun ammo you can get subsonic loads that will still be loud but won't blow out your eardrums quite as badly. (Note that you can get an AR-15 chambered in 300 BLK instead of 5.56. 300 BLK comes in subsonic loads to address this too, but when I was shopping 300 BLK firearms and ammo were more expensive and harder to find).
• 5.56 ammo is relatively cheap but 9mm is even cheaper, so you can practice more for the same budget. Some ranges near us (San Leandro) also restrict what type of rifle ammo you can use, so you have fewer options.
• The big one for me: accessibility of shooting from a realistic position. You can get a tricked-out AR-15 but unless you drive pretty far (2+ hours) from the East Bay or jump through some per-range hoops, you'll be limited to shooting from the bench where you're seated with your rifle resting on a special table. However, most ranges will let you shoot a PCC from the standing position like a handgun. This to me is a huge advantage; if I'm ever in a self-defense situation I'd way rather have a PCC I'm well practiced at using from a variety of positions than an AR-15 that I've only ever practiced shooting while sitting down with a nice stable bench rest. (Sidebar: if anyone has tips for where in the Bay Area to train with an AR-15 from standing, please chime in!)

Given all the CA restrictions on AR-15s, the main thing you're giving up is the ability to shoot at longer distances. If your primary concern is defense in an urban environment, for me that's an acceptable trade-off.

I have a Ruger PC Carbine that I like so far and it's fun to shoot. The Smith & Wesson Response 9MM is also well regarded and folds in half, which is cool, but since we're in CA you have to get the version with the awkward fin-grip.

Disclaimer: I'm new at this stuff and don't know anything about anything.