I never used punishments either and my kid has been consistently praised for his good behaviour in any school he attended. He is nearly 16.
Not using punishment is a lot of work in other ways though, and requires a parent to be very truthful, consistent and reliable.
It is a state of mind in a sense and I understand that it can be really difficult to understand how this works for many parents who default to punishment.
It certainly is not about ignoring problems, rather it is about seeing things for what they really are. Why a certain behaviour is not right determines what a kid should do to make things right.
As an example, at 4 years old my kid had to limit sweets heavily due to being prone to cavities. One very early morning I found out that he had some chocolate and when asked her initially lied to me.
Our rule at the time was that, outside special occasions and holidays, he could only have sweets one day per week of his own choosing, but on that day he could have as much as he wanted, literally. Many parents would default to punishment for lying, which sets in my opinion a vicious circle.
So, as angry as I was, I took a step back and thought about the real reasons I needed him to behave in a certain way.
Which were having him to autonomously protect his dental health, and to avoid lying to me because I cannot help with things I am unaware of.
One thing it could not be allowed to be about was my feeling of anger for having been lied to and therefore slighted.
That's a bit many parents have trouble implementing, because anger takes precedence.
So I went to him and explained that I was fine with occasional exceptions, but I needed to agree to them and know about them, so I could help wash his teeth immediately after, which would tackle the only real issues, his dental health. it was my duty to keep him safe.
It never happened again and he also very rarely asked me for exceptions to be frank, which I always honoured no matter what. This is true for the sweets day thing too, some times I was so loaded with work that I only found the time late at night to go shopping for sweets of his choosing for the day after. I always did it, for many years the thing lasted, no matter how tired or busy, because it was my end of the bargain.
There are drawbacks to this approach. My son is too dutiful sometimes, and tendentially unforgiving to himself because he is wired to take responsibility.
This often leads to good results in life but can put too much pressure on a kid, dependently on their personality and what behaviours they mirror (I am tendentially a nose to the grind, dutiful person, and I came to think he has copied my behaviour a bit too much).
So, no system is perfect, it is a lot of work, but it works. You can have well behaved, self regulating kids without using punishment.