Apple pin doesn’t work, i can’t put any pin, pin button is locked

Your home language on the screen shot is not a real problem. For others looking, the English version is My Watch/Passcode

I think you are trying to set a simple 4-digit PIN (in English, Simple Passcode option). My first question is - Do you have a longer passcode already set on the watch? I think I see the option for Wrist Detection is set which should mean you have a passcode, and this could change how things work (Romanian? language so I'm not 100% sure?? but it is in the expected place on screen). However, the first option looks like it means "Activate Passcode" which should mean the watch passcode is NOT set. Confusing... because this should be orange (available to click) and if a passcode is set it should change to "Turn Passcode Off"

You have looked in the Watch app on your iPhone. The same options should be visible in the Settings app on the watch (Passcode). See if the settings on the Apple Watch match the phone app, or if you can access what you want from the Watch.

The other possibility is you have a work-issue iPhone where the employer's administrator has locked some of the options.

Now you know the way I'm thinking about this problem it might give you a clue for the next place to look.