I'll ask you to take the time to figure out the total amount of time you've spent actually running as a DM. Make a guess. Take the total number of years you've been trying this. Then figure out approximately how many times a month you've spent sitting in the DM's chair. Then make a reasonable guess at how many hours each running lasted.
Suppose we take a baseline candidate: we'll call him Paul. Paul has been running for two years. For about four months at the beginning, he ran about five times. Then he ran every week for about six months, for a total of 26 more times. In the last year, he's run once every two weeks, about another 26 times. Paul has run 57 times. Paul figures these runnings have been about 4 to 5 hours long. We'll say 4.5 and multiply that by 57, for a total of 256 hours.
57 sessions sounds like a lot. But let's compare it with something else.
Last year, Paul got a job as a full-time line-cook at 37.5 hours a week. They gave him two weeks cross-training on most of the kitchen stations ~ 75 hours ~ and then got him settled on one station, where he stayed for twelve weeks: 450 hours. Paul had never worked as a cook before, so it took most of that time for him just to get comfortable with the restaurant: to learn the menu, to barely master the most basic of knife skills, to physically adapt to the temperature on the line and get used to being around very hot surfaces and a lot of boiling substances, like oil. Paul's hands are nicked and cut up, he's got little burns everywhere and he hasn't even remotely begun to develop the calluses a cook gets on the hands and fingertips. To the rest of the kitchen, at 525 hours under his belt, Paul was a NOOB.
But Paul kept at it. He's been working for 52 weeks now, with not many days off (cooks rarely get holidays, because they don't get paid for them). We'll say a week of sick days and lost hours. Paul knows this restaurant, now. He's had a total of 1,912.5 hours at the job and guess what: if Paul were to go work another restaurant, one he doesn't know, it would take him another four months to get comfortable there. It takes me three months and I have 14 years experience; and I'm really smart, as my boss keeps telling me all the time, given the morons she will describe to me.
If Paul puts out his resume and claims one year of experience, no one in the business will think he's experienced. They might hire him if he's young and eager-looking and is prepared to work for poor wages; but they won't think he's experienced.
Now, the reader should go ahead and look into their own industry and occupation and ask themselves if a year experience is treated as "experienced."
How many years does it take before you're a veteran? On the whole, I'd say about four years. 7,600 hours. On the job. Talking specifically about the time spent actually doing that job.
Here's the point. You tell yourself you're not a "good" DM. You hold yourself to that standard. Well, maybe you're not. But if the reason includes your coming up with a number of hours less than 2,000, then give yourself a break.
With DMing, you haven't got anyone there to train you. You haven't anyone standing next to you telling you how to make a map or build an adventure. You've got no paycheque, no intrinsic threatening motivation to make yourself run or improve at running. No one is there to say if you don't get your shit together, you're fired. You're free to learn at your own pace, which practically guarantees your pace is zero movement unless you're obsessed.
Give yourself a break. You're putting in hours, you're learning, you're watching people play, you're getting something out of every session: and if you don't prove yourself to be a genius with 1,100 hours under your belt, get off your own back. You're being stupid about this.
Making a sandwich isn't hard, dropping fries into a fryer isn't hard, mopping a floor isn't hard. But if you're not used to doing it really, really fast, yes, you're going to have trouble adapting to the work. It takes time to see the big picture.
DMing isn't hard, either. But it's strange, it's complicated, there's a lot to remember. It takes time to see the big picture.
Give yourself a break.