I bought a new (original) PS4 controller, but why does my left stick react differently?

I have a question and thank you in advance! ^^

If I move the left stick downwards to the left and upwards, the movement or sensitivity is very slow, so that I can't move well in fast games. But when I move the stick to ⬆️⬇️⬅️➡️↗️↘️, the sensitivity is quite normal, so you can play with it as normal.

I've already switched it on and off and reconnected!

Press the reset button on the back with a toothpick or something, if you haven't tried that yet.
I would look for instructions on google how to do exactly that so that it works correctly.

I also heard somewhere that you can calibrate the sticks extra by moving them in certain directions and pressing something else or something.
But I'm not sure if this really works or I have now spontaneously found no instructions for it. So if that exists and you find it, you can try that too.

If this is only the case with a single game, it may also be due to the game settings. Even if I was surprised somehow…