Some other things that help beginners - starting with your hands on the ground when kicking up is easier than coming from standing, since you can remove a lot of variables. And also kicking up to a split handstand (i.e. keeping your kicking leg down) and finding balance there before gathering the legs helps a lot too. Your centre of mass will be lower and you'll have more levers to use to find balance. A straight handstand is actually the hardest of the basic variations to balance. This is a good video on this: https://www.youtube.com/watch?v=zNyGK6z7iKo.
Keep at it! I think these articles claiming to get you to a handstand in 30 days are kind of disingenuous - it takes nearly everyone much longer than that to hold a static handstand for, say ~20 secs (i.e. requiring finding balance, holding it and then rebalancing).
Interesting thing about this one is that he doesn't put is palms down but balances on the fingers and thumbs. I put the weight on my palms, most youtube handstand explainers say that's ok.
Source: gymnast for over a decade in my younger years
Edit: to add, most people don't have the shoulder strength to hold a handstand, so doing workouts to strengthen your shoulders and upper back is going to contribute a lot more than just doing handstands alone.
This video looks like it might help: https://www.youtube.com/watch?v=tOLOojV9kB8
The same principle applies to a handstand, but it is instead your shoulders, pecs, and upper back. I was being a bit broad when I said shoulders, sorry.
Source: breakdancer in my younger years, used to practice together with gymnasts.