I still very much vouch for a shotgun and especially the DP-12. It is reasonably short, yet looks extremely intimidating. You have a 10rd capacity limit in California so you'll only get 2x5rds, 5 per barrel. That's already the max, you won't get more with any other gun either and it should be more than enough. About recoil, that's ridiculous. Host body weighs less than 70kg and I can shoot 50 rounds in short succession. You will have no trouble with recoil. Yes it's harsh in the beginning but you'll quickly get used to it.
An AR-15 is ofc another great choice even if it has to be California compliant and with 10rd mags. Biggest con for me is you really need to be sure of what's behind your target. Rifle rounds fly very, very far. You don't want to hit a child a mile away. Also you'll go deaf if you fire rifle rounds inside a building. In any case you should also try out an AR.
Regarding pistols, this is the hardest part. Ideally you should always - always carry a pistol with you if that is legally possible. Try to get a concealed carry permit. Guns are useless for home defense if they are tucked away in a safe. You should at least carry your handgun in your home. So you need to find one you're comfortable with and the right holster. The G17 is great but it's designed for open carry in external holsters by military / police. Even a big guy like you will probably find it uncomfortable to carry this thing with you. Again - try it out as well as the smaller G19 and ofc the 1911 and whatever else you get your hand on.
I would however strongly recommend staying with 9mm for the beginning. I am generally not fond of .40 for your only handgun for a simple reason - ammo price. You absolutely need to practice shooting. A lot. And .40 will cost you almost 50% more than 9mm, with negligible to outright doubtful benefits. Modern defense 9mm ammo is nearly as effective as .40 with less recoil, less weight and for less cost. Almost all western law enforcement and military uses 9mm, even the FBI went back from .40 to 9mm. From a practical standpoint 9mm is the only reasonable handgun round just like 5.56 is the only reasonable semiauto-rifle round in the west. This is the stuff you can buy in bulk and easily shoot large volume as a beginner. You're American, you can always buy more afterwards. But start with this. It's already expensive enough.
TL;DR
The only thing that matters is your ability to safely and effectively use the guns your have, models are much less important. Get what you are comfortable with and can afford to shoot regularly.