Like it sais in the describtion my character doesn't have a nameplate, and nameplates for other characters are only renedered when they are very close to me. I already maxed the rendering distance and tried all namplate options, but with no succsess.

For the render distance use this on a macro or something

/run SetCVar("nameplateMaxDistance", "6e1")

You can change the 6 to a 10 for further distance if you want, I don't know why Cvar setting from addons isn't working currently.

As for not having a personal nameplate, that's why I'm here too.

That cvar is purposefully disabled on classic, and the render range is (supposed to be) limited to what it was during vanilla. That workaround is an exploit.

The personal nameplate doesn't exist on classic. There's no way to enable it, and the old in-world floating names aren't nameplates and can't be modified by add-ons.