I don't see any problem here. You are shooting more than fine for you intended purpose; defensive shooting. Shooting tiny groups is a totally different thing. When I practice defensive shooting and I'm moving around a bit, I do NOT shoot tiny groups. Can I shoot small groups standing still while shooting rapidly? Yes, but only because I do it all the time. I shoot once or twice a week. Which is about 300 to 500 rounds a week depending on the week. But shooting is part of my business. I have to test my products.
How do you get good at anything? I don't care what it is. Practice, practice, practice, and more practice. Sure there is some innate skill involved, but as long as you are somewhat coordinated, there is no reason you can't learn to shoot well with practice.
One other thing I noticed. I'm a terrible bowler. But sometimes a little tip or word of advice goes a long way. A guy who knew how to bowl well saw me bowling. He came up to me and gave me one tip, one simple pointer. I did what he said and my score has been better ever since. I don't bowl (practice) enough to become a good bowler. But that tip helped me out and improved my game. A good shooter may be able to watch you shoot and see a little thing you could do better, and that tip with practice could make a huge difference. But with enough practice, you would probably figure out that tip for yourself.